I have had very good success with platelet rich plasma injections (PRP) for this problem. Platelets contain growth factors. In this therapy, your own blood is drawn, and spun to obtain a high concentration of platelets. The concentrated platelets are injected into your tendon to deliver the concentrated growth factors and induce a healing response. This treatment ihas had about 80% success rate.
I will be curious what response you get from the dr on here. Good luck.