 You may also have another small biopsy performed from the inside of your mouth in the area where the cells that might become cancerous are located. The biopsy will be performed by your doctor and will be sent to a lab for testing. At months 3 and 12, the doctor will also count and measure any red or white patches on the inside of your mouth. Biopsies will be taken after 3 months of treatment and at the end of 12 months of treatment. The tissue will be tested to see if there are any cells that might become cancerous. 