I am not a stitching expert, but according to my research it seems like people stitch a wound differently from a split in clothes.
To stitch a split in clothes, we just need 1 long stitch and wind it around the split into a spiral shape.
Can we say "my T-shirt has a stitch in its sleeve"?
To stitch a wound, we may use many small stitches separately as the below picture.
Suppose that we stitch a wound just like stitching a clothes split.
Is it correct to say "he has a stitch in his head"?