Clean the wound thoroughly with mild soap and warm but not hot water and make sure you don't see any feathers inside it, In my experience wounds tend to be perfect places for feathers to get pulled off and shoved into. Dogs have pretty dirty mouths so infection is something to worry about. Cleanliness is your friend.
Dry the wound thoroughly by patting it, don't rub it if possible.
apply neosporin without pain relief. And if there is any blood or any way for the other chickens to see it... Keep her separated from the rest of the flock. Chickens love to eat chicken.
You may want to consider giving her some boiled egg also to make sure she eats well since she probably wont be feeling that great and may act lethargic. In that case also separate her because she could get bullied away from the food by the others.
I've had a hen lose about 40% of the skin on her upper thigh to a dog attack and she lived but she needed lots of TLC.