Used needle and thread (4)
(Other definitions for sewn that I've seen before include "joined together" , "Needled" , "Joined by stitching" , "Fastened with stitches" , "Joined with stitches" .)
'used needle and thread' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for sewed that I've seen before include "Fastened with thread" , "Used needle and thread" , "Stitched" , "Did needlework" , "Darned" .)