I never had it done. I think it's used mostly by dentists. There was a discussion here about its accuracy, and false positives. I went to four different ENT's through the years, three oncologists, and none ever used the brush biopsy. It could be anything, especially in the mouth, where probably hundreds of conditions can cause it, but it is good you're being proactive, and should show your doctor, especially if the condition is still there more than three weeks. I don't know if the doctor would want to watch and wait if it can't be identified, and cancer ruled out, and your prior history, not saying it is. I had a white spot back of gum, wisdom tooth that was getting infected. I had to have the tooth extracted, and do 30 HBO treatments.
Good luck.