Radiation therapy can cause side effects to your skin. The side effects you have depend on the type of cancer. They also depend on where the tumor is and the radiation therapy dose. They also depend on your general health, your medical conditions, and also medications you are taking. Keep in mind that side effects don't affect how well the radiation therapy works on your cancer.
Some skin side effects take several days or weeks to develop. Some skin reactions may occur days, weeks, or longer after your treatment ends.