Tinnitus can be a manifestation of the SNHL you have, due to nerve weakening. Since you have improvement with Injections into the ear drum, continuing the rest of the course would be good. In addition there could be some improvement with Zincovit and Ginkobiloba tablets, but you will possibly benefit more from tinnitus retraining therapy, which is offered at more audiometry centres.
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vitamin supplements. Consider tinnitus retraining therapy