Anxiety Support Group
Anxiety is a physical condition marked by intense and persistent feelings of distress, fear, angst or dread. General anxiety caused by routine day-to-day stresses usually passes quickly and is experienced by almost everyone at one time or another. However, such feelings that linger over time and are very difficult to cope with, and which lack a clear cause, may indicate...

Every time you feel your pattern (writing out what happens when where how who what) look for what you want to do instead.
Distraction to change what you are doing.
With anxiety being natural, try breathing, relaxing and tensing your facial muscles to focus the feeling in a different way. Best wishes.
each time you notice you are biting you check. Then find something else to do.
Or chewing gum may help?