How can I fix this book problem, and could I be charged?

I don't think you would be charged. Like you said, there is nothing wrong with it other than the residue, so I don't think so. I once turned in a book with blood splatters on all over it and the teacher didn't charge me. I think you''ll be fine on that. But with the residue. First off, DO NOT USE NAIL POLISH REMOVER. It would take it off, but would also take off the color of the textbook. Goo Gone works, but depending on the material, it could damage a book cover. (Would be fine for those shiny covers on paperback books, but if your book cover is porous, the scrapbook stuff is better. Doesn't damage paper.) Scrapbook stores carry a sticker remover that is made for removing stickers from scrapbook pages without damaging the paper. That could work, but I don't know what it is called. Hope this helps.