Yes -you need to complete your treatment protocol. My tumor had totally vanished at 3 weeks but I had to complete my last three weeks anyway. The side effects you are having are typical and will continue for some time even after you are done with treatment. This is especially important since it is a recurrence. Ask the doctors for some meds to ease the pain and other side effects you arer having. I missed a few days due to machine downtime and once because I was too ill. They will add more days to compensate for it. You must receive all of the Greys of radiation that you were prescribed.