Nothing would happen. The OMRs are scanned for the bubbles that you have marked and not other minor scratches or mishaps. So you needn't worry about that. As NEET iis held in a pen and paper mode, it is understood that there is a scope for such minor scratches and so there is nothing to be worried about. If you have appeared for NEET 2020, for a complete list of colleges that you may have a shot at, please use our College predictor: https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer