Hi, Virginia, Please forgive me if I have missed information about your Mom, but I don't know if she has a peg tube or is going to try to get all her nutrition by mouth during radiation. You can research trismus on this website- it can be a serious side effect of radiation and can lead to severe consequenses if not dealt with. As to the pain management during radiaton and the other side effects of rad., your Mom and her immediate caregivers should be on top of this daily. IE: you may need to be VERY vocal about what she is experiencing [don't wait weeks to tell someone] and insist on another approach to the problem. Be proactive at all times because it will help everyone down the road. Amy in the Ozarks