Sclerotherapy involves a chemical injection of medication into the vein that causes it to close and eventually be absorbed by the body. This is used to treat smaller varicose veins and spider veins. It is a relatively simple procedure that requires no anesthesia. The needle that is used is so thin and the sclerosing solution is so mild that the discomfort is usually minimal. A compression stocking is worn for two weeks during the day to guard against blood clots and to promote healing