Hi, I agree i think it is PN flaring up because of the stress of the spinal tap and all that goes with it and also because of the resultant pain he has in the neck causing it to flare in the feet.That also happens to me, i broke my toes recently and it set off pain in the other foot also. Its just our brains interpreting the damaged nerve signals. So, if he has a pain in his neck, the brain could be interpreting the garbled signals from his foot as pain also. I also agree with taking B12 and B1 and if the pain keeps up , getting an interferential therapy unit.