With this type of spidervein removal, a small amount of "sclerosing agent" such as concentrated saline will be injected into the veins. This medication will burn the surfaces of the inside of the vessels and will cause them to close. Though the vessels will no longer function, there is little risk to surrounding tissue once healing is complete as new, smaller, non swollen vessels will take over the function.
After this treatment, you will most likely be required to wear tightly wrapped pressure bandages or support hose for several days and be limited to light activity. Two or more sessions may be required for complete effect.