I think my fear of a spinal tap is more to do with simply the idea of them
shoving a needle in my spine. 
As far as the headache. I had an uncle who had to have a spinal tap done once. I dont remember what for, I was really young. At the time his best friends dad as an anesthesiologist. I think I remember he said his friends dad did something to put liquid back in his spine? To re-float something? That made the headache go away. Know anything about that?