a bite is a bite. I've been told that when a dog gets to that level, it is nearly impossible to turn around.
This is not true. Dogs bite for many reasons, not necessarily because they
are aggressive! I have been bitten by Buddy when he was much younger
over a piece of bread that I tried to get out of his mouth, using Ceaser
Millan's method

After that incident I took training very seriously with
him. Today he would not think to do such a thing.
Buddy also bit the groomer. Why, who knows but he just refuses to go
back to her. He had his reason but can't tell me.
He's a loving wonderful pet. Smarter than any dog I have every owned.
He loves people and most other dogs.
I think this dog needs his own home. Some dogs are just Alpha dogs
and need someone to understand them and correct the problem.
THis is a perfect example why there are so many dogs in pounds and
rescues. People just do not understand their actions and are lost
as to what they can do to trun it around. But most are not BAD DOGS.
Please call a rescue, they can help.
Good luck,