I know it's easy to get extremely scared when you search and look through symptoms online - it always seems like it's the worst possible condition, when in fact, it most likely is some far far more benign condition.
Like in your post - you're terrified that you have mouth or throat cancer, but chances are far bigger that you simply have yeast infection of the mouth. Typical sigh of yeast infection is developing white/ yellowish coat on your tongue, together with swollen taste buds and changed taste, in general.
So, what I'd recommend you is to see your physician and get a prescription for anti-fungal medication that's used for mouth infections, or if you're having problems with money or insurance, you can ask for over-the-counter yeast infection medication - even though it would be best that professional takes a look to confirm what is going on,
Wish you all the best,