Flushed if ever I shrink trousers (8)
I believe the answer is:
feverish
'flushed' is the definition.
(thesaurus)
'if ever i shrink trousers' is the wordplay.
'trousers' indicates a hidden word (to trouser can mean to contain or hold).
'FEVERISH' is hidden within 'if ever i shrink'.
(Other definitions for feverish that I've seen before include "frantic" , "Restlessly excited" , "Frenzied" , "restless state" , "hectic" .)