Someone else here uses Zonalon with success. I can't recall who right now...you can search it. People taking AIDs drugs use Zonalon too for their foot PN.

I use Biofreeze when I have severe burning, which is not often anymore, but still appears now and then.

The other creams are used by many people with severe pain.
The RSD forum has members who have posted about compounded pain transdermal gels. The recipes vary from doctor to doctor, because certain doctors feel certain things are more useful, than others.

When I get burning, it is mostly on the tops of my feet, not the bottoms.

You will want to make sure you don't have athlete's foot fungus there on the bottoms. It can lie dormant in the skin and not cause lesions, but it can still cause burning. Aggressive use of Lamisil cream for 14 days, would be a good experiment to see if that is your culprit.