Lichen planus
I had Lichen Planus on my skin, not oral, about 10 years ago. I think it was because I was eating too many Omega 6 oils in processed foods or "junk food", which contain wheat and gluten. I forget where I found this answer as I've had several computers since then...I found it online. Anyway, one "cure" is to take Omega 6 oils...whether fish oil, flax, etc. And, to stop eating processed foods that of course contain wheat and gluten. As well as "processed oils and fats". Mine did go away.
It has returned because, once again, too many Omega 6's. So I'm starting all over by taking some fish oil and have once again removed processed crackers, chips, etc from my diet. Also, I suspect it could be part of a gluten sensitivity that I have had for a long while. So...no wheat in any form...bread, crackers, processed foods, gravies, noodles, pasta, puddings, donuts, sweet rolls etc. I'm naming all these foods because so many people do not understand "wheat" and the many foods that it is used to make. It helps to read labels, too, because wheat is in EVERYTHING. Once I found a component of wheat in a generic taco sauce that had given me a symptom. You'd be surprised.
It is very easy to cut wheat from your diet if you eat only fruit, veggies, unbreaded meat/poultry/fish, nuts, dairy, tofu. Think of what you CAN eat rather than what you shouldn't eat...then it's easy. A good book is Wheat Belly, which outlines a meal plan - or conscious eating - that doesn't include wheat.
I also want to mention that one symptom I had 20 years ago was severe heartburn. By process of elimination, I figured out that every time I ate even the smallest amount of "wheat", I would get this heartburn. So I did stop eating wheat for a long time. But as with many allergens, I had a craving for it, so it crept back into my diet at different times. I suspect that many of my health issues have been exacerbated by my wheat/gluten sensitivity..this includes IBS, lichen planus, severe heartburn and acid reflux, an eating disorder, depression, anxiety, possibly ADD/ADHD. I also have friends with
Rheumatoid Arthritis and ulcerative colitis who have gone completely off wheat and
Sugar and voila! all symptoms are gone.