Based on the initial description of a
grapeGrape seed oil like mass, this does not sound like a
hypertrophicHypertrophic cardiomyopathy neuropathy. The perineurium is the wrapping around a nerve (like the plastic around a electrical wire). A perineuroma is a enlargement of this covering in a focal area of the nerve. My advice is to obtain the official biopsy report, and then investigate further.
Regarding the healing of a cranial nerve. When nerves are not functioning properly it can be due to compression of the nerve or interuption of the nerve. If a nerve is compressed then the recovery it typically very good and typically takes months, but can recover over years. If a nerve is interupted, then the nerve has to re-grow, and this can take months to years depending on the distance which it has to re-grow. However, this is assuming that the nerve path remains intact. I hope this helps explain some of your questions.
Good luck