As for a hole such as this in a dress, shirt leggings or other article, the way to do it is to cut a patch the exact size and shape as the hole, then sew the patch in using a baseball stitch. This way the patch leather will be neatly inserted in the hole without overlapping it. In the above photo, I used a whipstitch, and that, along with the white thread, make the stitching obvious. So in subsequent patches, I’ve always used the baseball stitch. You can even sew the patch to the dress with stitching on the underside, going only through the edges of the hide. That way no stitching shows on the front.

Patching Holes in Buckskin: Step by Step