Heard you spilled wine over skinhead with rash (6)
I believe the answer is:
Here is my best explanation:
'rash' is the definition.
(I've seen this before)
'heard you spilled wine over skinhead' is the wordplay.
'heard' shows a homophone (sound like).
'spilled' indicates an anagram.
'over' means one lot of letters goes inside another.
'skinhead' becomes 's' (head letter of 'skin').
'you' is a homophone of 'u'.
'wine' is an anagram of 'nwie'.
'nwie' enclosing 's' is 'nwise'.
'with' acts as a link.
(Other definitions for unwise that I've seen before include "Rash", "Foolish", "Injudicious", "Lacking sound judgement, maybe foolish", "isn't sensible", "Foolhardy", "Not sensible or prudent", "Ill-judged" and "Not sensible, foolish".)