I am very sorry to say but unknowingly or not being in a good presence of mind, you have done one of a big mistakes of such exams. The OMR sheet is directly scanned in the Bio-metric machine which is given an input of reading those encircled bubbles only to find your roll number.

Now that you have already committed this mistake, I advice you to meet the superior people concerned with the exam and ask them only if anything is possible. If anything goes wrong invigilator is there for that only.

Next time onwards please take care properly.

Thankyou.