Red acne marks from acne, known as post-inflammatory erythema, take a long time to fade because they come from damaged blood vessels under the skin caused by inflammation.[1][3] When a pimple gets inflamed, it hurts tiny blood vessels, leaving behind pink or red spots that show through the skin, especially on lighter skin tones.[1][3] These marks are not scars in the indented sense but leftover redness from the healing process.[1][3]
The skin heals slowly on its own. For mild red marks, it can take 6 to 12 weeks to start fading, and longer if the inflammation was bad.[1] Deeper or cystic acne makes more damage, so the redness hangs around even more because the body needs time to repair those vessels.[1][4] Picking or squeezing pimples worsens this by adding extra injury and keeping inflammation going.[1][2]
Sun exposure makes it worse too. UV rays boost blood vessel activity and slow down healing, so without sunscreen, red marks can last twice as long or get darker.[1][3] Skin type plays a role. Lighter skin shows red marks more clearly and they fade slower than brown marks on darker skin, where pigment cells react differently.[1]
Collagen repair is another reason for the wait. Inflammation breaks down collagen in the deeper skin layers, and rebuilding it happens gradually over weeks or months.[3][4][7] Hormones, oily skin, or ongoing acne can keep the area irritated, dragging out the process.[1][7] Daily care like niacinamide, cold compresses, and sun protection speeds things up a bit, but full fading still needs patience.[1]
Sources
https://www.pokonut.com/blogs/pokonut-blogs/how-long-does-it-take-for-acne-scars-to-fade
https://www.psmedical.com.hk/en/blog/acne-health/acne-scars-recover-naturally/
https://www.kins-clinic.com/blogs/what-are-the-main-acne-scar-types-a-skin-friendly-guide-with-treatment-options
https://www.london-dermatology-centre.co.uk/blog/acne-scarring-back-chest-treatment/
https://syraaesthetics.com/treatments/acne-scar-treatment-nyc/
https://www.pristyncare.com/consult/acne-scars-for-years-is-complete-skin-clearance-possible/
https://heartaestheticshobart.com.au/skin-concerns/acne-scarring/
https://rejuvadermatology.com/conditions/acne-scars-in-venice-fl/
https://slmdskincare.com/blogs/learn/the-5-kinds-of-acne-scars-how-to-treat-each-type
