You mentioned having a clenched jaw in the past, then a relaxed jaw now. Do you think pressure from clenched jaw puts pressure on lips by pressing them together?
I still had EC lips when I tried daily posture exercises by a posture expert. I admit that I'm not very active or don't exercise to use up energy. However, I know of some former lip biters on here who are very active. But I have celiac disease which is known to cause peeling lips in some cases having nothing to do with posture...unless the disease itself makes your muscles weak. I didn't notice a diffrence when I tried posture exercises, though.
So, I'm going back to pressure from the clenched jaw?