Teen trouble (4)
I believe the answer is:
acne
'teen trouble' 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" , "Inflammation of glands in skin" , "Adolescent spots" , "(Inflammation causing) spots" , "Cane for the teenager?" .)