Was upset over the bandage (6)
I believe the answer is:
swathe
'bandage' is the definition.
(I know that swathe is a type of bandage)
'was upset over the' is the wordplay.
'upset' indicates anagramming the letters.
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'was' is an anagram of 'swa'.
'swa'+'the'='SWATHE'
(Other definitions for swathe that I've seen before include "Wrap in several layers" , "Swaddle - cut strip" , "Wrap in bandages - broad mown band" , "Wrap; bandage" , "Strip cut by a scythe" .)