Changed, and hence, made better (8)
I believe the answer is:
enhanced
'made better' is the definition.
(enhancing is a kind of making better)
'changed and hence' is the wordplay.
'changed' is an anagram indicator.
'and'+'hence'='andhence'
'andhence' is an anagram of 'ENHANCED'.
(Other definitions for enhanced that I've seen before include "Improved in quality" , "Improved (upon)" , "Improved or increased the value" , "Heightened" , "Increased number" .)