Why isn't Bystolic covered under BXBXTX? I am allergic to the other classes of BP medication. Now I am having an allergic reaction to the Amlodipine and BXBSTX is telling my dotors' office they will not cover the Bystolic.

I have been diagnosed with HBP and was prescribed a drug that my sister had a severe reaction to.  So the doctor's office tried to prescribe the Bystolic which is the medication that my sister now takes,  the request was denied and I was prescribe Amlodipine. Now 6 weeks after starting amlodipine I am experiencing an allergic reaction.  Can I get the Bystolic covered now?