Hiii bingi
I wish u had perform well in 12th....yes there is a way....after results are decleared than on cbse official site they announce the link of copy re evulation....u can go there and choose your subject for revulation. ...after some days the u had to apply for photocopy of subjects there you can pick up ur doubt que which u want to give for revulation....you had to pay for each que.....and yes you had to pay for each sub...
Hope u like the answer. and keep asking we are always there for you And dont forget to upvote