<Link Below> shows pictures inside of snake's mouths. There are various snake pictures, some of them however are corn snakes. You were worried about the coloration of your snake's mouth. See if any of these apply.
https://www.google.com/search?q=pict...'s+mouth&*
I am also enclosing a picture of my snake eating a mouse. His mouth looks a bit "Bluish" in this photo. I assure you, my snake is happy and healthy. I can not speak for your's. Perhaps you could post a picture of your snake's mouth and let some of us see it.