If there's a way to prove that, go to the head of his department about him damaging your schoolwork and inappropriate behavior for an instructor. If he's the head of the department, go to student resources or make an appointment with the Dean/Headmaster/whatever term your school uses. As to potential evidence, if the school has cameras in classroom like the room for the messier art/craft subjects, I'd see if you can get that pulled. If not, you can probably use how dry the sculpture compared to how dry it should have been if you had left it uncovered, and some classmates as witnesses that you stored the project correctly. You can also try to grin and bare it, but I know from my clay sculpting classes that the idiot could have cost you months of work, and since he is refusing to own up to his **** up, he sounds like he need a reality check, for those things and his inappropriate behavior. So, I'd suggest reporting him, over the "do nothing" route. I would suggest doing it even in the highly unlikely case he apologized for either part, or both. Teacher's that act like him have always been assholes on a power trip taking out some misfortune in their life out on their students.

Ohmigod my teacher is rude like that as well