Using vine charcoal (which erases easily) I sketch in a few optional arm poses and sketch her face in through the old arm. Any posture that changed the height of her shoulder would also alter the curve of the back and spread of the rib cage so I don't want to do that.
The important lesson here that I still have to keep reminding myself is that if something isn't any good then you can't ruin it. Be fearless, make changes, draw over the parts you don't like. What's the worst that can happen? I was ready to throw it out before making these changes so what's to fear?