It is very informative and helpful to the readers here, especially the lurkers and the people who will first visit this site in the future, to read stories where someone's cheilitis was cleared up, and to know the cause of it. Thanks for taking the time to post.
We don't often get to hear stories like yours, because the many people who have cheilitis and who solve it by following the typical first steps to eliminating it that are suggested by doctors (such as stopping using certain toothpastes or mouthwashes) never end up finding this forum and staying on it, trying everything under the sun, out of desperation.
Just because your cause was pretty simple and one of the first things that doctors suspect of causing cheilitis, it doesn't mean that your cheilitis was any less of an annoyance to you or that it can't be a good data point for others.
I believe that anyone who has cheilitis who doesn't have a fungal/viral/bacterial infection, who doesn't obsessively lick/bite or drool on the lips, and who doesn't have cancer probably is having an allergic reaction to something in their environment, whether or not that substance ever touches their lips physically. The allergy can work through the immune system and just show up on the lips.