Spots expert touring north (4)
I believe the answer is:
acne
'spots' is the definition.
(skin condition causing spots)
'expert touring north' is the wordplay.
'expert' becomes 'ace' (ace can informally mean very good).
'touring' is an insertion indicator (touring can mean going round).
'north' becomes 'N' (synonyms).
'ace' enclosing 'n' is 'ACNE'.
(Other definitions for acne that I've seen before include "Skin rash" , "Face problems" , "Problem to face in" , "Skin problem, mainly of teenagers" , "Spotty skin condition" .)