Use skincare which is contain brightening & whitening agent like Arbutin, Tranxemic acid or niacimide..
unfortunately my skin doesn't like niacimide ingredient..my skin tend to redness & dull... so sad :(
A good brightening product might be Shea Moisture Coconut & Hibiscus Radiance Moisturizer. This is a product for your face and though I haven't used this one, I have used the body lotion from the same line and it did great for my skin. This product contains Songyi Mushroom Extract, which is an effective, natural brightening agent. Though some of the ingredients (Cocos Nucifera Oil, Jojoba Oil, and Vitamin E) are rated on this cite as being possible causes for acne, if you don't have incredibly acne-prone skin it probably wont be an issue. The ingredients are natural and safe, a reliable brand I've used for a while now.