Hi Swati, I would agree with Cheryl and Eric. My father had developed a sore on his right tongue 3 months after radiotherapy (for his left tongue) and it was bothering us. We consulted the doctor and he adviced Biopsy but I was reluctant for another biopsy and asked for PET/CT first and if required, follow up it with biopsy if something suspicious comes up. Thankfully, it came all clear.