I used dr fred summit skin whitener on my face but now my face is brown and my body's real dark, has anyone used fair and white how does it work? How fast does it work? I want my skin to be a little brighter when I go prom shopping in three weeks.

If you want brighter skin the skin lightening isn't the way forward.
There's AHA that you can use. They come in masks, peels, soaps, creams, lotions, etc. It will renew your skin and make it brighter. Just remember to use sunscreen, minimum SPF15. Also, AHA should bring your skin back to normal again.