Hearing those words "Well hey, we did one thing, but that other thing, it may be permanent. The nerve will grow back at about a milimeter a day so give it a year." Such words were crushing to me when I learned the nerve pain and ancillary damage effects would be a forever thing in my life. I so feel for you.
Mine not being a HIP situation, I cannot speak specifically to the matter for you, but were I to learn such information from a neurosurgeon, I would next be back in front of my physiatrist to ask " are there options??" Why would I do this? Because the trust I have in my physiatrist/board certified pain management MD is tremendous. He tells me like it is. You have not mentioned a physiatrist in your situation, but maybe if you have a someone in that arena, you may visit with them for a second opinion.
You and I have shed tears of pain, and I am very concerned that you NOT be left with a hopeless and helpless perspective of life. Talk to a pain doc, that's my vote.
Prayin for ya,
Mark56