I have been struggling with this habit since I was a little boy, I will suck in my lower lip in and bite down on it with my back teeth, sometimes for a few minutes at a time. Im Constantly chewing, biting or poking the white swollen tissue with either my tongue or finger. At this point it has become a habit and strees doesn't seem to affect it, I just l Iove the way it feels...until it starts to heal ouch! It hurts so bad the only way to stop the pain is to chew/bite the sore open again. Really a nasty habit