Herpes Simplex Virus I, what you are calling a cold sore, can take up to 14 days to resolve. If you are not there yet time wise, you are way ahead of needing to find out what this is. If you have gone over the two-week mark, then it is time for someone who is trained in these matters to have a look see.... given that you say you have had a cold sore elsewhere in your mouth; the odds are that this too is a viral outbreak of some sort. Also stress is a trigger for those that have HSV to have outbreaks, and you are definitely under stress. There are many things that this could be that are benign and not cancer, I won't go into the long list here, but believe me, 90% of the lesions that doctors see are benign and resolve on their own. When you hit the three-week mark you need to have an answer that this is an aphthous ulcer or something like that, or a biopsy. If the doctors that are seeing you cannot tell you with certainty, then a simple 5-minute biopsy and a $50.00 lab bill will. In the meantime while you are waiting for the days to tic away, try to remain collected and calm.... the stress will only aggravate your HSV I, and potentially cause new outbreaks.

By the way you do not have to hit a return in the little window that you enter your posts in, the type will automatically scroll to the next line when it is ready to. I edited your first post to take all of those out so that it wouldn't be 5 miles long...

IF and when you have to go for a biopsy, the people here will talk you through things and be there for you as your stress level goes up and down. Until you know for sure... don't get too worried.