I'm similar to you in the mine has improved of late but it's still not healed, and every morning I have a thin white layer of skin but only around the inner part of my bottom lip.
Every day i wipe it off and every day or two it comes back.
So it does seem like the wiping away of the skin is the issue, I am determined to leave mine now and see what happens.
I've left it a week to a week and a half before, and it doesnt seem to get any worse, but it annoys me to the point that I always give in and wipe it away.
The answer has to be leave it but im finding that hard... I'm even more determined after writing this post though.