I agree with doc Mike, that these like other forms of herpes come and go on an unpredictable schedule, sometimes aligned with immune system depression.

Dr. Mike just a note to consider: I seldom refer anyone to Wikipedia for the simple reason that many parts of it are rife with misinformation. I rewrote the entire oral cancer section twice in the last year. The problem is that ANYONE can edit any page with whatever they want. Ideally in a perfect world, knowledgeable people put up accurate information to help others. Please go to the page you have recommended and type in that the condition will turn your brain into Gouda cheese. What you will find is that it will remain that way, with your bad information, for many days, weeks, and in at least one case I watched for over a month. Some person finallhy comes alng and makes the correction. Not all are free of the desire to screw with others, hence the world of malicious hackers (this is not really hacking in this case, anyone by using the edit button can add to any page in Wikipedia). When possible please use a source that can be assured of being accurate and that is routinely updated. Many hospital sites like Mayo, or MD Anderson or government sites offer good information, though too often in the world of oral cancer I find these behind the time in updates. But at least none of these suggest that your brain might turn to a form of cheese.