Why do I keep biting the same spot on my lip accidentally, and what do I do to make it better now, and keep it from happening in the future?

Chomping on some salad, and some of my lip got in there somehow. Same spot as normal. I have scar tissue in my lip from an accident in that spot. it is just like a small loose knot. I suspect this plays a role.

Anyway, I also probably do not take enough care especially if I am rather peckish.

Now that I have once again bitten my pitiful lip, I suspect it will soon become ulcerated during its healing, which is much worse then the actual biting of the lip.

Woe is me…