Cockney's borough reported skin complaint (4)
I believe the answer is:
acne
'skin complaint' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for acne that I've seen before include "(Inflammation causing) spots" , "Skin problem, mainly of teenagers" , "Adolescent skin disease" , "Pimply skin condition of adolescence" , "Spotty complaint" .)