Mark's out of mascara (4)
I believe the answer is:
scar
'mark's' is the definition.
(mark left by an injury)
'of mascara' is the wordplay.
'of' indicates the answer is hidden within the clue.
'SCAR' is hidden within 'mascara'.
'out' is the link.
(Other definitions for scar that I've seen before include "Injury mark - cliff" , "area of wound" , "Gordale - - , Yorks" , "Trace of an old injury" , "Disfigure" .)