Bemused, blame doubt developing after dance party (15)
I believe the answer is:
discombobulated
'bemused' is the definition.
('discombobulate' can be a synonym of 'bemuse')
'blame doubt developing after dance party' is the wordplay.
'developing' is an anagram indicator.
'after' means one lot of letters go next to another.
'dance party' becomes 'disco' (I've seen this before).
'blame'+'doubt'='blamedoubt'
'blamedoubt' with letters rearranged gives 'mbobulated'.
'mbobulated' after 'disco' is 'DISCOMBOBULATED'.
(Other definitions for discombobulated that I've seen before include "Confused" , "In a tizz" .)