See a blemish (4)
I believe the answer is:
spot
I believe this is a double definition.
'see' is the first definition.
(thesaurus)
'a blemish' is the second definition.
(spot is a kind of blemish)
(Other definitions for spot that I've seen before include "Lady Macbeth: ''Out, damned . . . .!''" , "small amount" , "jam > stain" , "Dirty blemish" , "[NIGHTCLUB]" .)