Mary,

It can be a hundred things, and at your age most likely is not cancer, but you need a definite diagnosis of what it actually is if not t preserve your physical health then to maintain your mental health.

The worrying and not knowing is the worst part so you may want to go ahead with a PET scan or a CT scan. You need to find a doctor that can define for you exactly what this is, someone who will stay with you through treatment and make sure the desired results are getting accomplished if this is thrush. If not, insist on a physical diagnosis of the problem and a treatment plan that will show results