Chances3;
Time... Your good ear has to learn to compensate. You probably lost more good vestibular function than you think when the nerve was severed.
VRT ( Vestibular Rehabilitative Therapy ) can be performed by a Physical Therapist trained in such. Something to ask Dr. about.
About benzos; Xanax is considered one of the most addictive with a short half life. If a benzo helps, maybe considering asking for a long acting one as Valium or Klonipin. But, they are addictive as well.
Re; "Quick spins" or longer episodes of 'true' vertigo', meclizine, phenergen, or dramamine are worth the sleep if you truly get sick to the point of vomiting and the true vertigo doesn't relent. I've been hospitalized 3 xs for incapacitating vertigo lasting at least 24 hours each episode. As always, ask your Dr. before trying these things on your own. Valium will make you more sleepy than Xanax, and meclizine, etc. are additive ( synergistic effect ). EG; 1+1=3