I don’t know how it happened, but somehow, one of the bunnies managed to move the incredibly heavy barrier between the bunny rooms, and they got into the same room and fought while I wasn’t watching…
I thought they weren’t hurt at first, but then I discovered a little blood on Mr. Bunny. I examined him, and he isn’t injured. But then, I discovered a big tuft of Ms. Rabbit’s fur with a big piece of bloody dried skin attached to the bottom. 
So, I examined her. On one on her shoulders, she has a patch where there’s a layer of skin missing. It’s really shiny, moist, and a mix of pale white (her skin color), pink and red. It’s about the size of a quarter. It wasn’t bleeding, but it looked really , really nasty. It looked like there was a whole layer of skin pulled off.
EDIT: I can now also see lots of thread-like blue and red veins just under the skin, so I know it’s really deep.
What should I do?