jcab...I split this question into it's own topic and deleted the other 2 identical posts from the other unrelated topics you posted it in..It is quite ok to start your own thread here

and welcome to RTB.
Now then...what to do....first off what not to do. Please NEVER feed your snake a live rodent again. If you peruse through the old threads on this site and read a caresheet or two you will discover many reasons why...mostly having to do with exactly what just happened to your snake. It is not uncommon for a rat to kill even a very large snake. Can you maybe enlighten us on other conditions the snake is kept in? what kind of cage, how is it heated? what are the cold and hot side temps both at day and at night? How large are the rats you are feeding? How often do you usually feed?
My guess with so little to go on, is that rats have been continually biting your snake over a period of time and just now finally one got him good enough for you to take notice. When this happens, often times snakes become afraid of their own food and won't eat and continue to let them chomp on them. Please do yourself and your snake a favor and get some frozen rats