The first one i had done back in October of 2003 made my feet hurt worse for a short period of time. I dont remember exactly but for around a week. The next 3 that i had, did not have that effect. My feet have become much more numb since October 2003. They are not pleasant tests, but i do not find them that bad either. I wouldnt hesitate to get another one, to keep track of the progression.