I can't address neck surgery, but I did have hernia surgery in the '60s during which they apparently severed a nerve in my abdomen/hip, leaving a rectangular area of about six square inches on my hip without feeling -- I don't recall how many years it took, but maybe ten years later, I noticed I had regained feeling in the affected area.

Also, some years ago I managed to pour some burning gasoline on my leg and ankle (Long story but for the record, I do NOT recommend this to anyone for any reason <grinz>) and it affected my ankle -- If I remained standing for any length of time, I would get an unpleasant tingling in the area -- Again, after 6-8 years, I noticed that the nerves or whatever had appeared to recover.