I'm another person who had a totally benign lumbar puncture. No pain. And not even the warned-of headache. My neurologist was very good, and did the procedure himself.

I have porphyria too, and it was dx'd some time after MS. It is possible for Porph to cause demyelinization, although rare. I believe that porph can actually set an MS situation going.
I may be the only one who thinks that, but then, hardly anyone knows or even talks about porphyria.
When you get into these strange diagnostic worlds, there will be confusion. Incidentally, I recommend the Swank diet should be tried--the very low saturated fat diet. Look it up, and blessings to you.