Get a blanket, wrap your dog in it and get to the vet NOW!!! The longer you wait, the longer your dog is going to suffer and infection will set in. It's possible to save the leg if you act quickly. If you wait too long, the leg may not be able to be saved and might have to be amputated/

This definitely needs a trip to the vet and right now. The vet will want to do primary and secondary care. You do need to know exactly what is wrong to do proper treatment.

you need to take her to the vet as soon as pssible or youre dog might never be able to grow it back regularly

call your parents now