Dear Anirudha, NEET is the entrance examination for admission into Medical, Dental and Ayush colleges across India. But to be eligible for that entrance examination, you should have scored at least a minimum of 50% in your 10+2 with Physics, Chemistry, Biology/Biotechnology and English as core subjects. It is 40% for SC/ST/OBC and 45% for PWD. Now if you look at this, the weight is equally distributed between your 10+2 and your NEET score. With anything less than the aggregate that you are supposed to score for your category, you cannot appear for NEET. And for qualifying for NEET, the basic syllabus is your 12th syllabus. So until you are good at academics in your 12th you won't qualify for NEET and unless you qualify for NEET, you can't get admission in a Medical college. 

Hi,

For admission in medical college, its only and only your NEET score that matters. It is the NEET score that will fetch you a rank which will further get you into one of the medical institutes.

As for your 12th score, its just for the sake of fulfilling the NEET eligibility criteria, i.e., you need to pass your 12th grade with a minimum aggregate of 50% in physics, chemistry and biology. This is true if you belong to general category. For OBC/SC/ST category students, this minimum score is 40% and for the PWD (people with disabilities), it is 45%.

So just focus on your NEET. 12th grade will easily be cleared with good score if you study hard for NEET as the syllabus for both is the same.

Good luck.