Anikhet, the qualification code is only useful for identifying your Educational qualification. It has nothing to do with your merit in NEET. If you score good marks and if you have documents for document verification, there should be no reason why your application should be rejected and your admission cancelled if you get a seat in MBBS. Now, your 12th marks have no bearing in your MBBS seat and so even if it cannot be corrected at this point in time, we would suggest you to leave it at that. When you attend the document verification process, make sure you have all the original documents handy and that is all that matters because you get a MBBS seat based on your NEET marks and rank in the merit list and not your 12th marks or highest qualification. These details are required for general information but this cannot rule you out of a MBBS seat if you get one. Do not panic.