Mistake made teen change for the better (8)
I believe the answer is:
emendate
'change for the better' is the definition.
Both the definition and answer are verbs in their base form.
Maybe you can see a link between them that I don't see?
'mistake made teen' is the wordplay.
'mistake' indicates anagramming the letters.
'made'+'teen'='madeteen'
'madeteen' anagrammed gives 'EMENDATE'.
Can you help me to learn more?
(Other definitions for emendate that I've seen before include "Fix" , "Correct" .)