Acne Marks: How to Tell Red Marks from Dark Marks and Acne Scars, and How Each Is Treated
Acne marks are the traces left on the skin after a pimple has settled. They are not all the same: they fall into three groups that differ in both cause and treatment. Many patients buy creams and apply them for a year without the marks fading, not because the cream is bad, but because it was the "wrong type" from the start. In this article, Dr. Patara Voravutinon, a dermatologist, explains how each type of acne mark differs, how to tell them apart yourself, why treating the wrong type does not work, and the evidence-based approach to each.
Quick summary: the 3 types of acne marks people confuse most
Red marks from acne (PIE, post-inflammatory erythema) are pink to reddish-purple marks caused by small blood vessels that stay dilated after inflammation. The colour briefly fades when pressed.
Dark marks from acne (PIH, post-inflammatory hyperpigmentation) are brown to grey-black marks caused by excess melanin produced after inflammation. They are very common in Asian and darker skin.
Acne pits (atrophic acne scars) are permanent depressions caused by loss of collagen. They are not a matter of colour but of skin texture.
Key point: red and dark marks are "temporary marks" that can improve, while acne pits are "scars" that need specialised procedures. Telling them apart first decides whether you need medication, a laser, or simply time.
How many types of acne marks are there, and how can you tell them apart yourself?
The easiest way is to look at the colour and do a gentle pressure test (diascopy) with a fingertip or a clear slide in good light.
If the mark is pink to red and fades briefly when pressed → it is usually a red mark (PIE), because the colour comes from blood in small vessels, and pressing pushes the blood out so the colour fades.
If the mark is brown to grey-black and does not change colour when pressed → it is usually a dark mark (PIH), because the colour comes from pigment in the skin, not from blood vessels.
If the skin in that spot is sunken like a pit and casts a clear shadow under side lighting → it is an acne pit, which is a different problem from colour.
In reality, one person often has several types mixed on the same face, for example red marks on the cheeks, dark marks along the jawline and small pits at the temples. Each spot should therefore be assessed individually rather than lumped together as "acne marks".
What causes red marks from acne (PIE)?
Red marks from acne are caused by small blood vessels under the skin that dilate and stay congested after acne inflammation. The body builds new blood vessels to repair the inflamed area. When the pimple settles, these vessels do not shrink back immediately, so a red or pink mark remains.
Features that help tell it apart:
More visible when the skin is warm, such as after exercise, a hot shower or hot weather, because the blood vessels dilate further.
The colour clearly fades when pressed (unlike dark marks).
Common in fair to medium skin tones and in areas that were very inflamed, such as pimples that were squeezed or picked.
Most red marks fade on their own over several months, but in some people they can last a year or more if inflammation keeps recurring or sun exposure triggers them.
What causes dark marks from acne (PIH), and why are they so common in Thai skin?
Dark marks from acne are caused by melanocytes producing too much melanin in response to inflammation. The extra melanin stays in the epidermis and partly drops into the dermis, appearing as brown to grey-black marks.
What doctors want patients to understand is that the more pigment the skin has, the more easily dark marks form and the more slowly they fade. Research has found that people with darker skin tones (Fitzpatrick types IV–VI, which covers most Thai people) develop dark marks after inflamed acne in roughly 65–85% of cases. This is why dark marks from acne are a much more common problem here than in Western content, which tends to focus on red marks.
Factors that worsen dark marks and slow their fading:
Sunlight is the strongest trigger for melanin, making marks darker and longer-lasting.
Squeezing, picking and scratching pimples makes inflammation deeper and longer, so the marks become darker.
Acne treatment that is too aggressive or irritating can also stimulate pigment.
Why telling red marks from dark marks apart matters so much
Because the mechanisms differ, so the treatments differ. Choosing the wrong type is not only ineffective but also wastes time and money.
Pigment-lightening creams (for example, melanin-reducing ingredients) work on dark marks but do almost nothing for red marks, because red marks are not caused by pigment.
Vascular lasers help red marks well, but using them on dark marks misses the target.
Conversely, choosing a pigment laser with too much energy on Asian skin can trigger new dark marks instead.
Put simply, correctly diagnosing whether the mark is "colour from blood", "colour from pigment" or a "pit in the skin" determines everything about how it should be treated. This is the part that product-selling articles and general beauty clinics often skip.
Evidence-based treatment of red marks from acne (PIE)
Principle: reduce inflammation, protect the skin and wait for the blood vessels to shrink back. Procedures are used for marks that are long-standing or very intense.
Calm active acne first — as long as new inflamed pimples keep appearing, red marks will keep forming. Treating the acne at its source is always the first step.
Apply sunscreen every day — although sun triggers dark marks more than red marks, sun protection reduces repeated inflammation and helps the skin recover faster.
Avoid squeezing, picking and harsh scrubbing — anything that re-inflames the skin prolongs red marks.
Topical products that can help — those that reduce inflammation and restore the skin barrier, such as azelaic acid and niacinamide, have evidence of some benefit.
Procedures for stubborn red marks — vascular lasers such as the Pulsed Dye Laser (PDL) are the standard for red marks, and lasers with wavelengths for blood vessels (such as Nd:YAG and pigment-and-vascular light devices) and IPL also have supporting data. Intradermal injection of tranexamic acid has been reported in studies to work similarly to PDL in some cases. All of these must be performed by a dermatologist.
Evidence-based treatment of dark marks from acne (PIH)
Principle: protect from the sun as well as possible, inhibit pigment production and speed the removal of old pigment, without re-inflaming the skin.
Sunscreen is the core, not an option — without sun protection, every dark-mark treatment will have little effect, because sun keeps stimulating melanin. Use SPF 30–50 or higher and reapply during the day.
Topical pigment-reducing agents with evidence — such as azelaic acid, niacinamide, vitamin C, topical retinoids (which help turn over cells and reduce pigment) and topical tranexamic acid. Hydroquinone works well but should be used in courses under a doctor's supervision, not continuously and long term on your own.
Additional procedures for stubborn dark marks — chemical peels and low-energy pigment lasers such as the Q-switched Nd:YAG (1064 nm) and the picosecond laser can break up pigment, but on Asian skin the energy must be chosen carefully, because overly aggressive treatment risks rebound dark marks, so it should be done by a specialist doctor.
Be patient with time — dark marks in the epidermis often improve within a few months, but if the pigment is deep in the dermis it may take several months to a year. Speeding things up with harsh methods often has the opposite effect.
What makes things worse: acne mark myths we often see in the clinic
Squeezing or picking pimples — increases inflammation and wound depth, and is one of the leading causes of both dark marks and permanent acne pits.
Rubbing on lemon or orange juice, or scrubbing with baking soda — strong acids and scrubbing inflame the skin and stimulate pigment further, and lemon reacts with sunlight and can cause permanent dark burn marks.
Using many creams at once until the skin peels and turns red — irritation is a form of inflammation, which in turn creates new dark marks.
Stopping sunscreen because you think the marks will fade on their own — this misunderstanding is what keeps dark marks around the longest.
Expecting strong lasers to work right away while acne is still inflamed — calm the acne first and then deal with the marks, otherwise new marks will keep appearing.
Do acne marks go away on their own, and how long do they take?
Red marks (PIE) mostly fade on their own in about 3–6 months if there is no repeated inflammation.
Dark marks (PIH) that are superficial usually improve within a few months, but those with deep pigment can take several months to a year. Sun protection and correct treatment clearly speed things up.
Acne pits do not go away on their own, because they are a permanent loss of skin tissue. Specialised procedures are needed to stimulate new collagen.
If your marks have not improved at all after several months of proper care, or you cannot tell which type you have, seeing a dermatologist for a skin examination (and a dermoscope when needed) will save more time and cost than trial and error on your own.
When should you see a dermatologist?
New inflamed pimples keep appearing. Treat the acne at its source first, because marks will keep forming if the acne is not controlled.
Marks have not faded at all after 3–6 months of proper care, or dark marks keep getting darker.
You cannot tell which type of mark you have, or you have both marks and pits and do not know where to start.
You want laser or other procedures. A doctor should first assess your skin type and mark type to choose a device and energy level that is safe for Asian skin.
Dark patches you are unsure are related to acne, such as those mixed with melasma or dark marks from other causes, should be properly diagnosed to tell the conditions apart.
At Siam Dermatology, treating acne marks starts with an examination to clearly determine whether they are red marks, dark marks or pits, and then planning individualised treatment, including topical medication and procedures such as pigment and vascular lasers, performed by dermatologists.
Frequently asked questions about acne marks
Do acne marks go away on their own, and how long does it take?
Red and dark marks from acne are temporary and can fade on their own if there is no repeated inflammation and sun protection is good. Red marks usually take about 3–6 months, while dark marks may take several months to a year depending on how deep the pigment is. Acne pits do not go away on their own because they are a permanent loss of skin tissue and need specialised procedures.
Which is harder to treat, red marks or dark marks from acne?
In general, dark marks with pigment deep in the dermis are harder to treat and take longer than red marks, but the difficulty also depends on depth and how long the marks have been present. The key is to identify the type correctly first, because the medications and lasers for these two types belong to different groups.
Does squeezing pimples really cause acne marks?
Yes. Squeezing, picking or scratching pimples increases inflammation and makes the wound deeper and longer-lasting, which is a major cause of both darker marks and permanent acne pits. Letting pimples settle on their own, or having a doctor treat them properly, greatly reduces the chance of marks.
How do acne marks differ from acne pits?
Acne marks (red and dark marks) are about "colour" on skin that is still smooth, and they can improve with medication and care. Acne pits are about skin "texture" that is sunken due to collagen loss, visible as shadows under side lighting, and they need collagen-stimulating procedures. Both can occur on the same face at the same time.
Which laser is used to treat acne marks?
It depends on the type of mark. Red marks usually use vascular lasers such as the Pulsed Dye Laser, devices with blood-vessel wavelengths, and IPL. Dark marks usually use low-energy pigment lasers such as Q-switched Nd:YAG or the picosecond laser, together with chemical peels. On Asian skin, the key is for the doctor to choose the energy carefully so that dark marks are not triggered again.
What can I apply to make acne marks fade faster?
For dark marks, options with evidence include azelaic acid, niacinamide, vitamin C, topical retinoids and topical tranexamic acid, together with consistently applied sunscreen. Hydroquinone should be used under a doctor's supervision. For red marks, the focus is on reducing inflammation with azelaic acid and niacinamide. For any type of mark, sun protection is an essential foundation.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed August 14, 2026
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