Red marks, dark marks or acne scars? PIE vs PIH vs atrophic scars, and what OTC can fix

Is it a mark or a scar?

The simplest test: run your finger over it, or look at it side-on in good light.

	PIE (red mark)	PIH (dark mark)	Atrophic scar	Hypertrophic / keloid scar
Colour	Red, pink or purplish	Brown, grey, slate-blue or darker than your skin	Skin-coloured, can be paler or discoloured	Skin-coloured, pink or darker
Texture	Flat	Flat	Dip or pit	Raised
Cause	Blood vessel changes after inflammation	Extra pigment after inflammation	Loss of tissue	Excess scar tissue
More common in	Lighter skin	Darker skin	Anyone with inflamed acne	Darker skin; jawline, chest, back
Fades on its own?	Usually, slowly	Usually, over months to years	Rarely	Rarely; can recur after treatment

Sources: AAD, DermNet PIH, Talakoub & Wesley, DermNet acne scarring.

The AAD puts it plainly: a flat patch of colour after acne clears usually isn’t a scar. It’s post-inflammatory hyperpigmentation. You can have marks and scars at the same time, and colour changes often sit on top of scars (DermNet).

Red marks (PIE)

Post-inflammatory erythema is the pink, red or purplish mark that lingers after a pimple, caused by new and dilated blood vessels. A dermatologist writing in Dermatology News notes it’s most often seen in lighter skin types and often follows cystic acne.

What helps:

• Time. DermNet notes colour changes after acne tend to fade over months or longer.
• Not picking, so you don’t keep re-inflaming the spot.
• Treating active acne, so new marks don’t form.
• In-office treatment. Vascular lasers (such as pulsed dye) and microneedling are used for stubborn PIE, though the authors say the evidence is mostly anecdotal. They mention azelaic acid and some other topicals may temporarily reduce redness, but there are no well-studied creams with long-term data.

Skin Realist check: there’s no proven over-the-counter cream for red marks. Products marketed for “post-acne redness” may make skin look calmer for a while, but time and sun protection do most of the work.

Dark marks (PIH)

Post-inflammatory hyperpigmentation is brown, grey or darker than your skin. DermNet explains that inflammation stimulates the skin to make more melanin. It’s more common, more intense and longer-lasting in darker skin.

If brown patches appeared without breakouts, often matching on both cheeks, the forehead or upper lip, that pattern is more typical of melasma. See what works for melasma and hyperpigmentation.

How long do dark marks last?

The AAD says:

• a spot a few shades darker than your skin usually fades within 6 to 12 months
• deeper discoloration, often slate blue to grey, can take years
• treatment can speed up fading

DermNet explains why: pigment in the top layer of skin (epidermal) responds to treatment, while pigment that has dropped deeper (dermal, often grey-blue) doesn’t respond to physical treatments and fades slowly.

What fades dark marks?

1. Sunscreen, every day. The AAD recommends broad-spectrum, water-resistant SPF 30+ sunscreen, ideally a tinted one with iron oxide, which also protects against visible light. Reapply every two hours outdoors. The AAD also says sun can darken acne and make it last longer (AAD back acne).
2. Treat the acne. Stopping new breakouts stops new marks.
3. Fading ingredients. The AAD lists azelaic acid, glycolic acid, kojic acid, vitamin C and retinoids (retinol, tretinoin, adapalene gel, tazarotene). Two of these also treat acne: the AAD says retinoids and azelaic acid can lighten dark spots left after acne, and DermNet notes azelaic acid is used for post-acne pigmentation, particularly in darker skin. DermNet also lists niacinamide among other options.

Cautions from the AAD:

• Avoid imported “lightening” products that may contain hidden steroids or mercury.
• Never put liquid bleach on your skin.
• Use gentle products and stop anything that burns or stings, because irritation can create more dark marks.
• See a dermatologist if OTC options don’t help; prescription or combination treatment may be needed.

True acne scars

Types of acne scars

According to DermNet, most acne scars are atrophic (depressed):

• Ice-pick: narrow, V-shaped, deeper than they are wide; the most common type
• Boxcar: round or oval dips with sharp edges, wider than ice-pick scars
• Rolling: wide dips with sloping edges that smooth out when the skin is stretched

Less often, scars are raised:

• Hypertrophic: raised, about the size of the original spot
• Keloid: excess scar tissue that grows beyond the original spot; common on the jawline, chest and upper back, and more common in skin of colour

Who gets acne scars?

DermNet lists moderate to severe acne (especially nodules and cysts), picking or squeezing spots, smoking, and longer-lasting or more severe acne. The AAD adds that early treatment matters more if a close blood relative has acne scars.

Can OTC products fix acne scars?

No. Creams can’t fill a dip or flatten a raised scar. The AAD says scars can fade but rarely disappear completely on their own. What OTC products can do:

• treat active acne so new scars don’t form
• fade the colour around a scar, which makes it less noticeable
• Mayo Clinic notes that sunscreen limits the contrast between scarred and unscarred skin

What do dermatologists use for acne scars?

Treatment depends on the scar type, your skin type and your goals, and often combines several methods (DermNet, Mayo Clinic):

Scar type	Options a dermatologist may discuss
Rolling	Subcision (loosening the band that tethers the scar), microneedling
Boxcar	Fillers, subcision or resurfacing, depending on depth
Ice-pick and deep scars	Punch excision or punch grafting; fillers
Shallow scars	Chemical peels, microneedling, laser resurfacing, dermabrasion
Hypertrophic and keloid	Steroid injections, silicone gel or sheets, lasers, cryotherapy

Things to know:

• Clear active acne first. DermNet recommends treating active acne before starting scar treatment.
• Darker skin needs care. Mayo Clinic notes laser resurfacing, chemical peels and dermabrasion carry a higher risk of colour changes in darker skin.
• Fillers are temporary, and keloids often come back even after successful treatment.

How do I prevent acne marks and scars?

From the AAD:

• Treat acne early, as soon as breakouts appear. Deeper breakouts are more likely to scar.
• Don’t pick, pop, squeeze or scratch. It increases inflammation, infection and discoloration.
• Keep your hands off your face.

Add daily sunscreen to limit darkening, and see pimple patches and spot treatments for what to do instead of squeezing.

When should you see a dermatologist?

• You have nodules or cysts, or acne that’s leaving scars: early treatment prevents more
• Dark marks haven’t faded after 6 to 12 months of sunscreen and OTC treatment
• You want treatment for indented or raised scars
• A scar is growing beyond the original spot (possible keloid)