You only have to worry about raised heads being a sign of a problem if her mouth is always open slightly
This can mean there is an infection in or around their mouth. This can be diagnosed as mouth rot at the vet.

BUT, infections smell funny so you would know. And from a distance, don't head butt your snake trying to smell in it's mouth. I did it on accident one time and I almost died haha

The typical panic button for snakes seems to be sitting in their water dish, the way it decides to sit around the tank doesn't really say much otherwise.