This is due to a combination of trauma causing extravasation of fluid and the mechanical effect of gravity. About two years ago I had an operation on the bottom of my foot. During this operation, some of the nerves were severed, leaving a large part of the bottom of my foot numb. This condition has not improved since the operation. It is very uncomfortable to deal with.
Nerves can regrow, but very slowly.
This is under optimum conditions. Also, even if they regenerate, the feeling will be a little different than prior to surgery. That is, you'll have feeling, but it will feel very different. Nerve grafts are possible, but rarely used due to a low success rate. I would avoid any further surgery.