Worries, scratching head and hair (7)
I believe the answer is:
tresses
'hair' is the definition.
(tresses are locks of hair)
'worries scratching head' is the wordplay.
'worries' becomes 'stresses'.
'scratching head' means to remove the first letter (the first letter or head is scratched out).
'stresses' with its initial letter taken off is 'TRESSES'.
'and' acts as a link.
(Other definitions for tresses that I've seen before include "The hair of the head" , "Long braids of hair" , "Long locks of hair" .)