WIC

The technical answer is that radiation damages not only the cancer cells but also healthy skin and tongue. According to the National Cancer Institute at NIH (National Institute of Health)
[quote]Slow healing and infection are indirect complications of cancer treatment. Both chemotherapy and radiation therapy can stop cells from dividing and slow the healing process in the mouth. Chemotherapy may decrease the number of white blood cells and weaken the immune system (the organs and cells that fight infection and disease). This makes it easier to get an infection.[/quote]
Unfortunately, this means that the your tongue can't heal normally.
Charm