Greedy, but happy about terrible acne (9)
I believe the answer is:
mercenary
'greedy' is the definition.
(thesaurus)
'happy about terrible acne' is the wordplay.
'happy' becomes 'merry'.
'about' means one lot of letters goes inside another.
'terrible' is an anagram indicator.
'acne' anagrammed gives 'cena'.
'merry' placed around 'cena' is 'MERCENARY'.
'but' acts as a link.
(Other definitions for mercenary that I've seen before include "Professional soldier serving in a foreign army" , "Paid fighter" , "Paid soldier" , "Bent on making money" , "One who fights for foreign country for pay" .)