Biting problem

I've been playing a lot of music that is very high recently, up to altissimo A. I noticed after playing this section the inside of my lip hurts because I am biting so hard. I can even see an indent where my teeth were.

Is there anything I can do to relieve this pain. Would moving up a reed strength help, or is a habitual thing I need to fix? My setup RN is either a Vandoren Blue Box 3s or La Voz Medium (jazz) on a Vandoren B45 mp and Vadoren Optimum ligature