I have severe exostoses in both ears, which has rendered me temporarily deaf. how much does the corrective surgery cost?

Exostosis: "It depends" on your insurance carrier, Medicare, etc. Some private ear surgeons (otologists) work strictly fee-for-service and cash only. They would give you the most direct answer. Other factors include getting surgery in one ear at a time vs both canals same procedure. Surgery is "day surgery" that CAN be done through the canal(s) and requires tissue grafts and packing.