Thanks for the query. I hope you visited a Dermatologist. Such a presentation is common with many Indian patients and before a treatment is begun, it is important to understand the reason for the occurrence. A skin biopsy should be performed and it will help securing the diagnosis and also provide vital clues about which drug can give more benefits. Treatment may take few months to be visible and should be done with precisely.
Meet an expert Dermatologist.
Avoid using a brush or loofah or any thing to rub the skin, it will increase the pigmentation.