An awful narrative — needs some nerve (5)
I believe the answer is:
ulnar
'nerve' is the definition.
(ulnar nerve is a kind of nerve)
'an awful narrative needs some' is the wordplay.
'some' indicates a hidden word.
'ULNAR' is hidden within 'awful narrative needs'.
(Other definitions for ulnar that I've seen before include "Relating to one of the bones of the forearm" , "Relating to a particular arm bone" , "of certain bones" , "Relating to a bone in the forearm" .)