I see that you aren't new here, that you posted a thread 14 months ago...
I don't know if you have been following the forum since then and have seen my previous posts, but if you haven't, I'd like to offer a couple of thoughts.
You said that your cheilitis was caused by taking accutane, and persisted even when you stopped taking the drug. That is a story that I've seen told over and over on the internet. I think that patients should be warned about this potential side effect of the medicine, because it's so long-lasting.
I don't know for sure what caused my cheilitis to start about a year ago -maybe fungus- but for the first 6 months, it was low-level exfoliation and irritation, kind of like constantly chapped lips that never got better. Then, in the summertime, my cheilitis drastically worsened. I think that was due to my trying out some vitamin A/retinol-containing face lotions and face washes which didn't work out for my skin, so subsequently I tried out some face lotions, astringents, and face washes containing AHAs (alpha hydroxy acids, glycolic acid, fruit acids). I was happy with one of the AHA face lotions I tried, so I continued to use it until last month, when, as a part of eliminating any possible skin irritant or allergen that might be causing my cheilitis, I decided to stop using nearly all of my face lotions for a trial period, to see if my lips would get any better.
For about the past 5 weeks, I've only used unscented liquid Neutrogena face wash to wash my face, and some benzoyl peroxide Acne
lotion on my nose and forehead. No lotions, no makeup. When I stopped using my face lotions in the early part of December, my lips immediately showed an improvement, and the terrible daily skin overgrowth and major exfoliation stopped right away. The skin got rapidly better, day after day. In mid-December, I absentmindedly put the AHA lotion on my face (because it had been a part of my daily routine for the previous 6 months, I reached for it out of habit), and within a couple of hours the cheilitis flared up badly. At least making that mistake gave me firm knowledge that the AHA lotion was a major contributor to my cheilitis.
I haven't touched the AHA lotion for about the last 3 weeks, and my bottom lip has continued to improve. So many layers of my lip were originally damaged with the cheilitis that it's taking quite a while for each damaged layer to grow out and fall off (each thin layer peels off in big pieces on its own about every 3 days, revealing slightly nicer-looking skin underneath each time). My lips feel smaller, softer, and happier each day.
I can tell that this gradual and calm shedding process is very different from the angry exfoliation and irritation that I was experiencing before. I hope this means that my cheilitis has gone for good, but I'm not going to be sure of that until there is no lip exfoliation at all. That will probably take another week or two.
So, if you are using any kind of face or body wash, lotion, cream, gel, or medicine that contains (even a tiny amount, even if it's just buried deep in the ingredients list and not advertised on the label) vitamin A, retinol, retin-anything; or AHAs, glycolic acid, fruit acids; maybe stop using it and see what happens with your lips.
I experience a lot of relief from washing my lips 4 or 5 times a day with an organic hand wash containing aloe, tea tree, peppermint, calendula, white tea, and coconut oil, and then from putting glycerin on them after each wash.
I tried a few days ago to go for the whole day without doing the lip washes and glycerin, and by nighttime, the condition, feeling and appearance of my lips had gotten worse. They were dry, scabby, not too happy. I don't think the cheilitis had started back up or anything, but I think that the soap and the glycerin do a great job at soothing and treating my damaged surface lip layers, calming them down while the deep layers are forming in a healthy way and gradually growing up and out.
So, I'd recommend washing your lips with a gentle soap made for human skin several times a day (after toothbrushing and eating), and then immediately putting glycerin on as a moisturizing method.
If you don't want to wash your lips with soap throughout the day, I would still highly recommend using glycerin as your only lip moisturizer/treatment. (It goes on shiny and slick, but it quickly dries to be invisible and matte, so don't worry that it would look like you have on girly lip gloss.)
I have found that any lip treatment that is oily or waxy is bad news for my damaged lips - chapstick, vaseline, mineral oil, olive oil, etc. Of the oils I've tried, pure coconut oil was the best of the bunch, but for me, the glycerin was more calming and smoothing.
By the way, grapefruits and all other citrus fruits are proven to irritate the mouth and lip skin. Fruit acids (especially citrus, apple, and pear) can be very intense, and they contribute to skin exfoliation. Their acids are so strong that they soften and wear away the hard enamel of our teeth. So you may want to rethink having a lot of grapefruits/grapefruit juice unless it's in the form of a pill, or unless you wash your lips with soap and rinse your mouth out with water after you eat it/drink it.