Endless fright and surgery reminder? (4)
I believe the answer is:
scar
'surgery reminder?' is the definition.
(I've seen this in another clue)
'endless fright' is the wordplay.
'endless' means to remove the last letter.
'fright' becomes 'scare' (scare is a kind of fright).
'scare' with its last letter removed is 'SCAR'.
'and' is the link.
(Other definitions for scar that I've seen before include "reminder of sword-fight?" , "Identifying mark" , "Mark from a wound left on the skin" , "Mark left by the healing of injured tissue" , "Disfigure" .)