I would just let her be and wait. It can take a week or more before you see improvements. Let her rest quietly. I don't see anything she can't heal up from if given a chance. The next 24 hours will tell. If she survives the night she will heal.I think I am just going to put her down. She is drinking properly, and can swallow it. Is there any hope?
I have almost culled a few that I swore wouldn't make it, but my husband said give them a chance. Just this spring a week old chick got a big circle of skin removed off her back, down to the muscle by a hen. It's now running around like nothing happened. Chickens are good at healing. She just needs quiet rest now in a cool, but not too cool area.