If she was neglected to the point of having a RI, mouth rot, burns, and at least one retained shed, it is probably safe to assume she was not given access to clean water. I would be worried about dehydration--I know long term dehydration has systemic affects on other reptiles, I wonder what could be going on from that? I think daily soaking is a good idea, just be sure to check the water temperature and replace as needed because water temperature drops quite rapidly. Good luck with her.
-Guy