Not everyone who smokes gets cancer and not everyone who drinks gets liver failure. Not everyone who gets a cut gets infected.
Everybody's body reacts differently to different situations. This logic that just because other people don't get EC when they get a wound on their lip, just doesn't make sense.
I am 100% positive that constant lip biting over years and years caused this. And it's more than coincidence that many people who have EC feel the same way. Believe it or don't believe it, but that's just what happened.