Patients who have had sclerotherapy have reported little discomfort. Some experience a slight to moderate burning sensation immediately after the injection, but this disappears within a few seconds. An ointment to soothe the skin and relieve the burning may be used. And a pressure bandage may be applied to prevent post-injection bleeding. Some physicians prefer to use elastic stockings. Others use compression bandages.

Sclerotherapy patients are generally advised to return to normal daily activity immediately following the procedure. Vigorous physical activity is discouraged for 24 hours, however. Walking right away after sclerotherapy is encouraged because it increases bloodflow through the remaining healthy veins that bring blood back toward the heart. Elevating your legs usually isn’t recommended unless large varicose veins have been treated.

Most patients experience no adverse effects from sclerotherapy, but some minor side effects have been reported. These include slight blistering that occurs when small amounts of the injected solution seep into the surrounding areas. This usually goes away with time, and additional treatment with bleaching agents can help.

Bruising around the treated area can result if the veins are unusually weak but eventually disappears. Fair-skinned people tend to bruise more than dark-skinned people. Clots sometimes develop at the site of the injection. Although not a major cause for concern, it may be necessary to remove these clots within 2 weeks to better allow the healing process to progress normally.

A small percentage of patients develop a network of tiny pink vessels that turn white when pressure is applied. This condition, referred to as "matte telangiectasia," usually disappears without treatment. But sometimes injection treatment is needed. Occasionally, patients have allergic reactions to the injected solution. When this occurs, a health care provider uses antihistamines and other medications to offset the reaction right away. When large varicose veins are treated, wearing support hose is recommended to prevent recurrence.