Seems I've done this forever too, usually inside left cheek. It gets a callous. When things get really bad I'll bite the external lip Until it bleeds and then peel skin when scab dries. Real classy. Sometimes trying another oral substitution helps, like chewing gum or sucking hard candies. Also can try pressing tongue to palette or pinching lips together. In meetings I play with watch strap and try not to peel finger skin. Sigh.