Very bad bruising after sclerotherapy when will it fade?

Sclerotherapy issues: Sounds like an extravastion or leaking of blood products from the injected veins into the sub dermal surrounding tissues. This could cause permanent staining. Best to return to see the injection doctor for treatment.

Depends on type: There are different types of skin discoloration that can occur after sclerotherapy & patients often define them as "bruising" even though they often are not. Typical bruises from blood cells escaping from the punctures will be "black & blue" & resolves w/i a week or so. Persistent tan coloration of the skin can be an occasion side effect (i.e. hemosiderin staining) & this can often last months.

Post sclerotherapy.: It is very common to get bruising post sclerotherapy and it can take several weeks to resolve. There are several things that you can due to decrease bruising including wearing compression hose, applying wet heat to the bruised areas and applying a topical cream. I have been using Dermaka topically with very good results.