Actually yes someone has taken 3-4 years to cure it by leaving them alone. As far as Im concerned this is the ONLY person who has ONLY used to leave it alone method and gotten 100% cured. Everyone else who has gotten cured by leaving their lips alone have done other things. Some people found an allergen that was causing this (I believe they have contact dermatitis not EC), and others such as Lees have done extreme candida diets.
So to my knowledge the only person who got 100% cured of EC, by JUST leaving them alone, was the guy who made the EC website, and he said it took him 3-4 years. Although I do believe he had EC for years before he began leaving them alone.