Repurposing curtains cut up, one uses needles (13)
I believe the answer is:
acupuncturist
'one uses needles' is the definition.
(acupuncture is a needles-based therapy)
'repurposing curtains cut up' is the wordplay.
'repurposing' indicates anagramming the letters (the same letters for a different purpose).
'curtains'+'cut'+'up'='curtainscutup'
'curtainscutup' anagrammed gives 'ACUPUNCTURIST'.
(Other definitions for acupuncturist that I've seen before include "Needle therapist" , "Cut up curtains (anag) - complementary therapist" .)