Alyssa, I don't think anyone will "flame" you. Things like this happen. I don't know that it would have been enough power to be fatal. Sure it probably would have hurt like hell. Maybe I'm wrong, but that's how I'd like to think about it.
You are a good dog mommy (or sister). I've been in similar situations several times. Not all were life threatening, but they sure made me feel bad. We learn from these things. It was meant to be that you happened to see him when you did. Now you'll be more careful about things like that in the future.