Gather matching yarn, a tapestry needle, scissors, and a small patch if needed
Turn the sweater inside out
Trim any loose threads around the hole
Thread the needle with matching yarn
For a small hole, stitch across the opening with small, even stitches
For a larger hole, weave the yarn over and under the surrounding stitches to rebuild the fabric
Pull the yarn gently to close the gap without puckering
Secure the yarn with a few small knots on the inside
Trim excess yarn
Turn the sweater right side out
Gently smooth the repaired area
Wash and block the sweater if needed to help the repair blend in