My advice would be to not do what you did....by your description, it sounds like you didn't put enough into knocking it out...or "stunning" it...it sounds like you only made him suffer.
The chances of the rat doing anything to your snake is slim to.....most likely none. our snakes are professional killers. Next time, feed live and if your snake doesn't eat, have a set up so that you can house the rat for a week, and then try again.