Get upset after month’s hot (7)
I believe the answer is:
febrile
'hot' is the definition.
(thesaurus)
'get upset after month's' is the wordplay.
'get upset' becomes 'rile' (I've seen this in another clue).
'after' is a charade indicator (letters next to each other).
'month' becomes 'Feb' (abbreviation for February).
'rile' put after 'feb' is 'FEBRILE'.
(Other definitions for febrile that I've seen before include "Very hot" , "Nervously excited" , "Of or involving a fever, feverish" , "Unhealthily excited" , "Delirious" .)