Unfortunately, this question is outside of my expertise, but the MayoClinic suggests that it is effective therapy for small varicose veins:
https://www.mayoclinic.org/tests-procedures/sclerotherapy/about/pac-20384592#:~:text=Sclerotherapy%20effectively%20treats%20varicose%20and,to%20reroute%20through%20healthier%20veins

This is outside of my area of expertise but I believe sclerotherapy is effective.