Relatives in salons win makeover (4-2-3)
I believe the answer is:
'relatives' is the definition.
(son-in-law is a kind of relative)
'in salons win makeover' is the wordplay.
'win' becomes 'w' (abbreviation in sport).
'makeover' indicates anagramming the letters (I've seen this in other clues).
'insalonsw' with letters rearranged gives 'SONS-IN-LAW'.
(Other definitions for sons-in-law that I've seen before include "They have married into the family" , "They're married to daughters" .)