Hello, I have heard that applying triphala powder face pack reduce the dark pigmentation on face and helps in skin whitening. Is it true and can it also be used for dark circles around eyes, as a pack over eyes. Please suggest me how to apply that face pack to reduce dark pigmentation on face, skin whitening and dark circles around eyes and mouth, and open pores using triphala powder face pack for oily skin. And how long should I use this to get fair skin and oil free skin.