I am 18 with acne scars & brown complexion please prescribe generic medicines and creams for spotless and fair skin?

Benzoyl peroxide : Bpo is a good place to start--there are many good over the counter preparations that you can leave on overnight and it will control mild acne. If you have moderate to severe acne, you are probably better off seeing a dermatologist and getting on more potent, prescription medication. The "scarring" you have noticed may be post inflammatory pigment, which will fade over time.