Do you have anything like Canesten duo capsule available in your country? This medicine is an antifungal that is not made for the mouth (it is made for the vagina) but it is edible.
If you are very desperate, maybe I can post you some medicines to try if that would be helpful.
Personally form my research, I think EC is a form of retention hyperkeratosis of the lips that occurs in response to chronic inflammation. A lot of people's biopsy results on this forum came up as showing hyperkeratosis. EC also looks very similar to the retention hyperkeratosis on this lady's face. http://escholarship.org/uc/item/7jt8s9n0
We just have to figure out what is causing the chronic inflammation. In my case, I'm quite sure it partly has to do with chronic dry mouth (or salivary gland hypofunction).