Hi Kim and welcome to Pet talk. Poor kitty. How does the tail look right now after your treatments of neosporin? I asked my vet about this for you and he said that the only thing they could really do would be to clean it up and treat it as an open wound and probably give an antibiotic just to be safe.
As long as it doesn't smell bad or look like there's an infection going on, it should be able to heal ok. Of course it's always a good idea to have a vet check it out, but if kitty doesn't seem to be having any problems and if it looks like it's healig ok...then just keeping it clean is the best course of action.
What did you name this kitty? So glad you took him in
**hugs**