Central Board Of Secondary Education [CBSE] — Need correction in 10th result

I am a student of class 10th from Sterling school Baragaon Babatpur Varabasi UP. I am not satisfy with my given marks. My previous result is 85 % but my school give me only 45% in bord exam. I talk about this with my principal, he said to me that my result is my result has been spoiled through board. So l bag requesting to you that give a change to school for to recreate my result. Like me, many students are got so lase percent in exam.