Hello there,
If you have failed in three subjects, then you need to sit for re-examination. The eligibility criteria for NEET states that candidates must have atleast 50% aggregate in their 10+2 level. So you must score the minimum required aggregate to be eligible for NEET. Coming to your query of two results, every year many candidates sit for re-examination to score the minimum required aggregate, and it doesn't create any problem in the long run. You get admission in MBBS colleges based on how you perform in your NEET. So don't worry, prepare for your re-examination.
Hope this answer helps you.
Good luck!!