Wrinkle-reducing injection (5)
I believe the answer is:
botox
'wrinkle-reducing injection' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for botox that I've seen before include "(Temporary) anti-wrinkle treatment" , "poisonous cosmetic" , "It's used to smooth wrinkles, temporarily" , "Agent removing lines" .)