Localized bruising and pigmentation at the injection site is commonly seen after sclerotherapy. It is often a result of inflammation from the sclerosant agent and very temporary in nature (usually clearing up in 6-12 weeks). Rare persistence can occur for a small number of patients up to 1-year post-treatment. If it worsens or shows no signs of improvement over several weeks, I'd follow up for an evaluation with your physician.
