Is she passing blood through her vent? How bad are the external injuries? Broken bones? If you think she can be saved, clean up her injuries, use an antiseptic on them, and make her as comfortable as possible in a quiet dark place. If you do believe she has internal injury, then you have to decide if maybe she should be put down. Or you may want to take her to a vet if you have one. Dogs can be savage. I wish you the best.