Try to gently open her mouth (if you are comfortable with doing it) to check and see if she still has substrate stuck in it. Foreign object caught in between teeth can cause mouth rot.

If she does, take a syringe/eyedropper/ear bulb (whichever you have) and gently rinse her mouth out. She should be able work most of it out by herself.

If all is clear, wait 3-4 days and offer her the mouse again. She probably just upset herself a bit.

Corn snakes are complete guts, I wouldn't except any long term effects from this. She'll probably be back to normal by tomorrow.