It depends on how bad/deep the hole is. How is she acting? Chickens can be amazingly tough (and equally delicate, it seems). I had a hen that had half of her comb torn off once, and I thought for sure she wouldn't make it. Her sisters actually pecked at the wound initially, so we separated her from the rest, cleaned her head with saline solution, then kept it covered with neosporin for several days. She healed just fine - it took about 2 weeks. She never looked the same after that (she had a funny head); but we loved her and she was all the more special to us for enduring the ordeal and making it though it.
I've also had to take a hen or two to the Vet from an attack by a dog. The vet stitched them up and they were also fine. Are you lucky enough to have a Vet who will look at your birds? It might be worth a shot if you are really unsure of what to do or if she is difficult to handle.
I hope for your sake she heals and is none the worse for the injury.
All the best to both of you,
Empathy