Patients may see immediate whitening or swelling of treated veins

https://medium.com/@merlenamlr/genetics-and-varicose-veins-how-sclerotherapy-addresses-inherited-risks-ad95b5ef346b

Patients may see immediate whitening or swelling of treated veins, which is expected; these changes settle as the sclerosant works and the vein progressively seals and shrinks.