This is a difficult situation as none of us can see or feel the problem. Photos are good but can't replace hands-on observations.
Taking in any food is a good sign and her drinking is important.
I think the next shed is going to answer a lot of questions. I would give her as much hands off time as possible(keeping the stress low) and play the wait and see game. You've got a Vet. involved so some professional advice is available.
My Vet. usually doesn't recommend blood being drawn since garters are so small and it requires a large sample.
Our thoughts and prayers are with you.
Keep us posted.