Mascara mishap (5)
I believe the answer is:
smear
'mascara mishap' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smear that I've seen before include "Badmouth" , "Dirty mark; aspersion" , "Slander - tissue sample used for testing" , "nasty mark" , "False report" .)