I know what you are going through, but stick with it. Most likely, the program for radiation that they have you on is overkill, but it has been developed based on studies of past patient histories and is not random. Abnormal activity could not be detected on my PET scan after induction chemo but I went through with 39 daily treatments on my head and neck. I never would have thought it, but it was tougher, way tougher than chemo.
But it is better to be extra careful and go through with it than to have to go through it all again in case they missed a few cells. Get back in the microwave and do some preventive measures to help you out with your healing like using skin cream and using cold compresses to remove the residual heat from the treated areas.
Look it sucks. But no matter how much it sucks, it is better than the alternative.