Teen's skin concern (4)
I believe the answer is:
acne
'teen's skin concern' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for acne that I've seen before include "Pimply ailment of adolescnce" , "Youthful problem" , "Face problems" , "Cane for the teenager?" , "Teenage spots" .)