Just finally got to read this whole thread. Kellie by heart goes out to you and Eddie - and do not blame yourself (just like I would!). I let Peaches off leash all the time when I think it's "safe" and like with a 3 year old - in the blink of an eye they can disappear or do something foolish. You are so lucky that Eddie doing something foolish didn't end is his being killed. And I'm soooooooo happy that he's doing so well. I bet he's feeling guilty over biting his Mom - he just couldn't help it since he hurt so much at the moment.
And I'm also so glad that you got the help you needed and the care you needed. If only most of our doctors cared as much as most vets that I've met.