I may have the same thing and have had it for over two years. I have been treated for everything under the sun and still have it. I have had my teeth dulled , 4 different month long treatments for yeast, 1 treatment for possible herpes, been to a Dr, dentist, oral surgeon, a center for infective diseases and everyone just through up their hands and said " I don't know". I have been referred to an oral pathologist outside Louisville Ky for my next stop.
The bad thing is I am starting to think about mingling with the ladies again after my wife's passing a year and a half ago and can't because of my mouth condition.
There is one thing that will knock out any yeast infection, potassium sorbate, you can get it at wine making suppliers, wine makers use it for stopping fermentation in wine. It is also in bread to retard spoilage. One tablespoon in a cup of distilled water. If you have jock itch that is persistent, daub this stuff on with a cotton ball and your infection will be gone in a day or so. Keep treating for a couple weeks after symptoms disappear. I jumped through the same hoops with a genital yeast infection and cured it myself with potassium sorbate after being circumcised and going through a bunch of treatments from various doctors.
I made a batch , cut off a Dixie cup, put a few tablespoons of my mix in the cup and stuck my tongue in it for as long as I could stand it, then spit it out and rinsed my mouth.. I repeated this treatment 3 times a day with no relief so I am pretty sure I don't have a yeast infection.
The next step up is called oral inflammatory disease, Google this term for some scary information.
