You really need to know the numbers for your B12 result.

If you are not in the US, I need the concentration also, for conversion to US units.

Lab ranges remain old and not updated to the newer levels considered "normal". Many doctors do not know this, and will
accept a low reading as "normal" because the lab says so.
If you are really low in B12 you may not know it even, and delaying treatment will result in more nerve damage.

In my experience numbness is worse than pain. Numb means that nerve impulses are not getting to the brain, for some reason.

In the foot that can be compression of nerves by the ligaments
that hold the foot together. In low thyroid, mucin a tissue is deposited there to compress nerves. My painful feet eventually became numb and only returned to function once my thyroid was adjusted.

Numbness can come from hereditary issues also. CMT is typically the cause. (Charcot Marie Tooth). We have a thread here about that:
http://neurotalk.psychcentral.com/thread121564.html

Also it may take years for a foot injury to flare up into PN.
I had a tumor removed from my instep over 50 yrs ago, and starting 4 yrs ago (I am 66 now) is when that ankle started to flare up and the scar now throbs. It took all that while for the nerves to grow back after all the damage done decades ago!

I would make sure you have Xrays of both feet...to show any spurs/arthritic changes, or sesamoid issues.

It can take alot of detective work to find answers for PN. So all you can do is keep looking.