Hello,

I'm assuming you mean that you wrote wrong question booklet number in CA Foundation Maths exam and then corrected it using a whitener and wrote the correct number over it. If this is the case, then you don't need to worry as such mistakes happen a lot among students every year and as we cannot replace the OMR sheet, the invigilators suggest to use whiteners.

It's perfectly normal and acceptable. You need not worry about anything.

Hope this helps,

Thank you