Hello. Thanks for writing to us at healthcaremagic The dark patches are actually post-inflammatory hyperpigmentation (PIH); Post-inflammatory hyperpigmentation may persist long after the inciting condition has resolved. If I was the treating doctor I would have asked you to use a skin lightening cream, containing one or more of the following skin lightening ingredients like Kojic acid, hydroquinone, glycolic acid, arbutin, tretinoin etc. These skin lightening ingredients act by either inhibiting new melanin synthesis Or by exfoliating already existing melanin Or by a combination of these mechanisms, when used in combination.. These are prescription products. I would suggest that you visit a dermatologist in your region for the needful. An Oral Vitamin C supplement once daily would help as well. Regards