In the Medicare space prescription tier and formulary exceptions are filled out and approved pretty often. You can ask your doctor to fill one out for you.
I know that it is frustrating when formularies(drug lists) change, but it is often done as a cost saving measure for the insurance company and consumer. Less cost for the insurance company should help with premiums as well.
If you have individual or a Medicare drug plan, you could look into changing your insurance carrier to get the drugs covered.
I personally had multiple doctors prescribe multiple ointments, inhalers, and pills to solve a skin rash. Finally one doctor pinpointed a chemical in my house that I was allergic too. The whole process was so frustrating. It’s good to hear that you identified the cause of your allergy so you don’t have to keep chasing the symptoms.