Hair worries, scratching head (7)
I believe the answer is:
tresses
'hair' is the definition.
(I've seen this in other clues)
'worries scratching head' is the wordplay.
'worries' becomes 'stresses'.
'scratching head' means to remove the first letter (the word's head is removed).
'stresses' with its initial letter removed is 'TRESSES'.
(Other definitions for tresses that I've seen before include "Long braids of hair" , "Long locks of hair" , "The hair of the head" .)