If it is prediabetes and nothing else contributing to your numbness, the actual treatment is getting those sugars levels down to normal again and keeping them down, you do not have to be a full blown diabetic to get nerve damage, i hope your neuro has advised you on this.

The numbness does not always mean the the nerves or cells are dead, they can repair in some cases once whatever is assaulting them ceases, they have in my case and i was in a prediabetic state as well.

I had a lot of numbness under the soles of my feet but not to the point that i ever lost my balance, perhaps if i let the prediabetic state continue the outcome might have been differant.

Brian