I hope everything comes uot all right for you're boy.I had my hand peeled back when I was a kid and it took me a couple of years to get over it.
I own two of dogs of my own so the idea of having to put one away sinks in.
Can you ever trust that dog again?

I would bring it to the vet and have it put away humanly.
Might even think about getting another dog of more friendly breeding to help you're poor boy deal with what just happened to him?