Unfortunately there just isn't much effort being put into reptiles in the Veterinary industry. More than there use to be, but still nowhere near enough considering how many pet reptiles there are now. My sister is in school to become a vet, and some of the stuff she has been taught was terrifyingly wrong. (things like bearded dragons don't need UV light etc.)
I think the most important thing right now is trying to find out what caused it. My guess is that she rubbed herself too hard on something, but it could also be an infection of some type. Maybe try pulling everything but the water dish out of the tub and draping a towel or something over it to provide security for the snake.