Cheeky blighter? (4)
I believe the answer is:
acne
'cheeky blighter?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for acne that I've seen before include "Problem to face in" , "Inflammation of glands in skin" , "Teenage skin blemish" , "Skin complaint" , "Skin affliction" .)