Apply a paste of turmeric+curd+ white sandalwood over face before sleep .let it dry. Wash it away in morning.

The phenomenon you are describing is something called post inflammatory hyperpigmentation. Basically, this is a normal reaction of the skin to an infection, trauma, or other damage in which as part of the healing process pigmented cells called melanocytes migrate into the healing area. This gives the skin a darker appearance. Fortunately, virtually all cases of postinflammatory hyperpigmentation get better on their own. This can, however, require weeks to months. The best way to speed healing is to promote general health of your skin. In other words, apply a good sun screen when you are out in the sun and use a good skin moisturizer to keep your skin supple...nothing else needed... Consult dermatologist for further help Regards