I'm Scared - I've Had A Problem With Thrush For

I'm scared - I've had a problem with thrush for some time, now I have a white round spot inside my mouth where my tonsil used to be. My dr is referring me to an ENT and said she is very concerned since my jaw on that side also,appears swollen and I have ringing in my ears, and recent bouts of vertigo that I'be never had before. I had head mri's in the last 2-3 years because of ongoing symptoms with vision and numbness. Wouldn't a cancer or tumor have been seen when they checked for brain lesions?