Acne Scar
Acne scars are lesions that appear as craters or pits in one's skin after the acne lesions have resolved. Acne scars are formed when the inflammatory lesions of acne are overhealed with the formation of fibrous adhesions at the site of acne lesions.
They are broadly of four types, ice pick, rolling, box scar, and hypertrophic scars. Rolling scars are easier to treat than the others.