Dear Bob: Of course I bite my lip whilst eating or chewing gum. The left lower lip. If there is a PD symptom, no matter how uncommon, you can be sure I have it and have learned to cope with it. I've had PD for eight, at least, years so bound to have a few, if not all, symptoms. I find if I chew food, or gum, on the right side, I don't have the problem. I frequently grimace on the left side lower lip so that "weakness" of whatever muscle puts the lip in a good spot for a good bite. And so it goes. Keep soldiering on. Life is still better than the alternative. Barbara Yacos [log in to unmask]