I’ve heard some good things about fluticasone propionate. Normally it’s an over the counter allergy med (nasal spray), but I saw a study where a lot of people that used it got their sense of smell (and by extension a lot of taste) back in about 5 days.
Worth a try, at any rate. They sell it at Costco and most drug stores.
That’s a referral to a series of specialists and probably an MRI or two at minimum. Cancer is a deeply shitty way to die, go talk to your doctor ASAP.