I never exfoliated, bitten, sucked, or licked my lips. I got EC from either the food I ate (caused inflammation), the overgrowth of yeast which celiac disease often causes, or sluggish liver. A sluggish liver works harder to clear toxins from food that is toxic to you.
I think most people with EC have stopped these bad habits (if they ever had them) to give their lips a chance to heal, but their lips have not healed. So, it has to be something more.