Lightening your skin is just toning the color of it evenly. You can try Kojic Acid (cream or soap form), a natural acid extracted from a mushroom. The other one is Glycolic acid, a natural acid that extracted from sugarcane and other multi-fruits acid.
Both of that are excellent for skin lightening, dries pimples, erase black spots and removes any kind of skin blemishes. It also helps for skin exfoliation and rejuvenation. Hope it helps you too!