you soaked, and dunked your snakes in mite spray?? thats definitely not good. i would put my money on thats what did it. you have to understand that even though safe for the snake when used properly (and soaking them in it is not properly) is safe, mite spray is still a pesticide. take the living animal to the vet and see if anything can be done, if not you jmight have to uthenize it so it doesn't have to suffer the poisoning (if that is the case). definitely bring the snake to the vet.