Of course, I can't say how many times but I'm sure I was biting something inside my mouth by accident at least a few times. I can't remember biting anything inside prior to EC though. Oh and when I bit them I don't think any "skin" was hanging after biting, but more like a little bruise caused by the pressure of the teeth, which of course all returns to normal.
Personally, my lips look okay throughout the day, but there are days where I wake up with white gunk. Thankfully no "skin" goes inside my mouth, and it really just ends where they meet. There's a distinct line between the inside of my mouth and EC. Are you willing to try that method? I can't say if 3 days would be enough to produce some result, but eating and drinking definitely "disturb" the mouth in their own way.