Sclerotherapy is the most common treatment for spider veins on your legs. During this treatment, Dr. Singh injects sclerosant — a mild, FDA-approved, chemical solution — into the problem veins to cause them to close. Your body absorbs these damaged vessels and re-routes the blood through other healthier vessels back to the heart. The number of injections you need varies and depends on the number of affected veins. A single session can involve multiple injections. Dr. Singh also places a special light against your skin to illuminate other underlying veins, which allows him to target hidden veins.