You should not worry about cancer. Cysts are
commonCommon cold at any age, and they are not related to cancer in any way. I don't know why your son has two--I don't even know for sure that the second one is a cyst. It may be another sort of under-the-skin bump (also noncancerous!) I advise you to leave it alone and show them to his doctor and not worry.
Take care.
Dr. Rockoff