Acne

Acne is an infection of the skin caused by changes in the sebaceous glands which usually happens during puberty. Acne can be treated with a solution of Bubotuber pus.

Acne is also a part of a Mandrake's maturing cycle; once their acne has cleared up, they are ready for repotting and, after that, reach maturity.

Eloise Midgen was known to have a bad case of acne, and many of her classmates at Hogwarts used her as the standard against which really bad acne was to be measured.

The effects of the Dumbledore's Army parchment jinx were stated in a generalized manner to make severe acne "look like a couple of cute freckles".

Moaning Myrtle is described as having a "spotty" face, suggesting that she suffered from acne when she died.