Your foot sounds like mine!

As you know, I am not an MSer. But I do have a terrible time with my left foot. I had surgery on it when I was 12 to remove a tumor. There was lots of nerve damage and it was numb for years. When the nerves grew back, they were mixed up and hurt alot. It swells at times and goes back down. I also sprained it in my teen years, and that might be a factor now too. I had new x-rays 2 yrs ago at the podiatrist's and they showed lots of bone spurs in the ankle.
I find if I flex that foot to aggressively, like going up steep stairs, it will flare terribly after for many days.

I find putting the new Aspercreme Lidocaine on the top of it where my scar is, turns off the overfiring nerves, and helps alot. It even takes down the swelling. (I don't understand that effect, but it is welcome none the less)

I find that the Aspercreme Lidocaine lasts one application over a couple of days or so.

There are alot of nerves on the top of the foot, and also ligaments that hold the foot bones together, which can become inflamed and compress those nerves.
Aspercreme Pain Relieving Cremes and Gels: Pain Relieving Creme with Lidocaine

This formula is almost as strong (80%) as the Compounded RX pain formulas, and many of us at PN use this with great success. It is over the counter at many stores and pharmacies now.