Friendly note on beauty treatment has lowered tone (6)
I believe the answer is:
social
'friendly' is the definition.
(similar in meaning)
'note on beauty treatment has lowered tone' is the wordplay.
I cannot really see how this works, but
'note' could be 'so' (musical note) and 'so' is found within the answer.
'tone' could be 'c' and 'c' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for social that I've seen before include "Relating to human groups" , "Relating to people living in groups" , "Official helping families with problems" , "Living in an organised community in Licosa" , "Sort of security" .)