Cats will instinctively lick a wound. Their saliva will help clean it out and stop the bleeding. Also their skin is not connected to their muscles in the same way that humans are, which is why it looks so strange to us. I've seen similar, though less serious wounds after catfights or car accidents and they really don't bleed much.
I would be concerned about rabies though. I would suggest leaving the cat at a vet for observation forwhatever the rabies incubation period is.
Vets don't charge much for boarding a cat.