Not coming back with certain bald patch (7)
I believe the answer is:
tonsure
'bald patch' is the definition.
'tonsure' can be an answer for 'patch' (I have seen 'bare patch' mean 'tonsure' so perhaps 'patch' could also mean 'tonsure'). I'm not sure about the 'bald' bit.
'not coming back with certain' is the wordplay.
'coming back' is a reversal indicator.
'with' means one lot of letters go next to another.
'certain' becomes 'sure' (synonyms).
'not' in reverse letter order is 'ton'.
'ton'+'sure'='TONSURE'
Can you help me to learn more?
(Other definitions for tonsure that I've seen before include "Shearing ?" , "Removal of locks" , "Monastic hairstyle" , "Monk's haircut" , "Monk's hairstyle" .)