I'd continue the Neosporin until I saw definite signs of healing (I'd put some on in the evening and just keep her out of the tank overnight in an escape-proof container with a cloth she could burrow under).
As for putting her back in the tank, I'd think twice. The other one is likely to go for the very area that's healed as well as other parts of the body (like the back of the neck). I have two male painteds, one of which started bullying and biting the other years ago. The one that was bullied lost part of his tail, most of his nails on one hand and had a nasty bite mark on his neck. They simply cannot be put together---even in a 300-gallon stock tank that I tried them in this past summer. They live in a 150-gallon stock tank that is divided down the middle and spend a fair amount of time swimming back and forth trying to get at each other (especially the bully).

