Actually the worst injury I have had from an animal was a cat, mind you at the time my dog was trying to eat the cat (it was my parents cat, the dog was on the chain but silly cat came too close even though she knew not to) and I had grabbed her head so she couldn't shake the cat to death and the cat was trying to protect itself, I ended up with bite wounds on the base of my thumb and on my forearm and a crud loads of scratches, 5 hours afterwards I was in so much pain I was crying, I couldn't move my arm it felt like I had a broken wrist and a broke thumb, never felt anything like it. 4 months on I still have the scars from the puncture wounds and most of the scratches and my thumb still aches. BTW the cat was fine, didn't even seem sore afterwards and my dog didn't have 1 injury the turd.
BL - I know some people don't like it but the best method I have ever found for getting an attacking dog off is to grab the dog by the back legs, lift up as high as you can and then when they release walk backwards. This means the dog cannot flick around and redirect onto you and leaves the least amount of damage on the dog being attacked, it is also a very quick way of separating the dogs.