Skye, I tried to write a response in the actual thread but then I had problems with the forum so hopefully this works.
As the other people said, there is no point thinking about the "what if's" you did the right thing, you saved your little boy which makes you a hero. Don't worry about the bruise, it couldn't be helped.
I don't even want to think about how scary that must have been. It scared me when Jazz is chocking on food, but I've never had to take major action like that.