I have been receiving Sclerotherapy on my legs for spider veins for six to seven years now. Within the last three years I have experienced a migraine headache immediately following the treatment four times and after the last treatment I experienced what I would describe as a "rush" and a feeling of lightheadedness immediately followed by a migraine. Is this something I should be concerned about? Should I discontinue the treatments? My treatments are usually only twice a year, about five to six months apart and only on one leg.