An acne scar forms at the site of an injury to tissue and are the visible reminders of acne breakouts. Causes of acne scars are the body’s inflammatory response to sebum, bacteria and dead cells in a plugged follicle. Two types of true scars exist; depressed areas such as ice-pick scars, and raised thickened tissue such as keloids.
Post-inflammatory pigmentation is discoloration of the skin at the site of a healed or healing inflamed acne lesion. It occurs more frequently in darker-skinned people, but occasionally is seen in people with white skin. Early treatment may minimize the development of post-inflammatory pigmentation, but sometimes this pigmentation change may persist for up to 18 months, especially with excessive sun exposure.