Protest over make-up artist? (4)
I believe the answer is:
liar
'make-up artist?' is the definition.
(I've seen this in another clue)
'protest over' is the wordplay.
'protest' becomes 'rail' (I've seen this before).
'over' says the letters should be written in reverse.
'rail' backwards is 'LIAR'.
(Other definitions for liar that I've seen before include "not straight [one]" , "Story teller?" , "Bearer of false witness" , "Teller of fibs" , "Pinocchio, at times" .)