With a NEET score of around 400 you’re in a solid position for  MBBS admissions under the OBC category especially in private colleges through state or management quota. Generally private college  cut-offs for OBC range  from about 480–600 but OBC candidates scoring 400 may still secure seats in mid-tier or less competitive private institutions where the management quota cut-off can drop to 150to 450. In some states OBC seats in government or deemed universities also open up around 400 marks. A score of 400 typically places you around the 90th percentile which is quite strong for reserved category admission. Official qualifying score for OBC is between 143–113 so you’re well above that minimum. To maximize your chances, apply promptly in state counseling and keep an eye on stray vacancy rounds in private colleges which sometimes admit  candidates with lower scores. If you’d like, I can help you list colleges in your state that  accept OBC candidates with near-400 marks