I'm so sorry that you are going through this! I, too, suffered sever skin burning due to radiation treatment. It was excrutiating; however, I "fortunately" have a colostomy so I didn't experience the "razor blades" or the "hot lava". It was definitely one advantage to the permanent colostomy! I had 3 weeks of 5FU 24/7 with the radiation treatments. Unfortunately, after the 3 weeks combination, my counts were so low that the chemo was stopped so that I could finish the radiation. With only 5 days left of my treatment, my pain and burning was so bad that my radiation oncologist gave me some time "off". He suspended the radiation for Thursday, Friday and Monday in the hopes that my skin would begin healing. He believed that he was not compromising the effects of the radiation by suspended it for those 3 days. It made the final 5 days much more bearable!
My "go tos" for relief were Domeboro on wet washclothes placed on the painful area and Silvadene cream. A warm bath provided some relief also.
It was a very painful experience, but now that I am a year from it, the pain is a distant memory. The skin healed remarkably quickly once the radiation was completed.
Hang in there!