I hv hyper pigmentation on my buttock and rough skin. What can I do to get my hip spotless and fairer as I m going to get married.?

Hydroquinone, laser. A good topical cream to try is hydroquinone. Laser works very well, and much more quickly for this as well.
Depends... ...On what is causing it, and from your description i can't really tell. Why not let a dermatologist examine you, determine what it is, and give you an appropriate treatment?