Near the armpit.

I stitched the torn area myself.

The sweater wasn't completely damaged, and it was a small hole that could be easily stitched up.

If the damage is small and can be fixed, we should do it immediately. It is important to repair things when you have the opportunity to extend their life and save money. If we wait or don't act on it, the object will get damaged further and we would have to throw it away.