Short patient comes about blister perhaps
I believe the answer is:
sac
'blister perhaps' is the definition.
(blister is a kind of sac)
'short patient comes about' is the wordplay.
'short' means to remove the last letter.
'patient' becomes 'case' (synonyms).
'comes about' shows that the letters should be reversed in order (I've seen 'coming about' mean this (about can mean backwards or around)).
'case' with its last letter removed is 'cas'.
'cas' back-to-front is 'SAC'.
(Other definitions for sac that I've seen before include "Traditional entitlement to hold court" , "Pouchlike structure" , "Pouch or bag-like structure" , "Distended membrane; pouch-like cavity" , "Membranous cavity" .)