IF the bubble is over dark that is the marking came out of the bubble then it depends on the extremum i.e., how far the ink is out of the bubble. As a result, there exist both the possibility. Its possible that you can get marks or you can't get marks due to the question it the OMR machine don't identifies it. But there are less possibility of getting negative markings for this.

To know more about NEET counselling visit the link below:

https://medicine.careers360.com/articles/neet-counselling

I hope this answer helps. All the very best for your future endeavors!