This is a great article from the Mayo Clinic that discusses the myriad of issues that patients who undergo Chemotherapy and
Radiation can experience.
Mouth sores can be painful and distressing. They can range from a mere inconvenience to a severe complication that may make you unable to continue your cancer treatment.
Cancer-related #mouth sores are sores or ulcers that form on the inside lining of your mouth or on your lips. The mouth sores appear burn-like and can be painful, making it difficult to eat, talk, swallow and breathe.
Sores can appear on any of the soft tissues of your lips or your mouth, including your gums, your tongue, or the roof and floor of your mouth. Sores can also extend into the tube (esophagus) that carries food to your stomach.
Chemotherapy and radiation — alone or combined — can cause mouth sores. That’s because these cancer treatments are intended to kill rapidly growing cells — such as cancer cells.
Some healthy cells in your body also divide and grow rapidly, including the cells that line the inside of your mouth. Unfortunately these healthy cells are also damaged by chemotherapy and radiation.
Read full article Mouth sores caused by cancer treatment: How to cope – Mayo Clinic