Hello,

As per the NEET 2020 marking scheme, four marks to be awarded for correct answer, while one mark to be deducted for wrong attempt.

So yes, if you done many incorrect questions, it will definitely have effect on the final marks.

Yes  if you have negative marks in neet it will effect your overall score.  Even if you have had many mistakes in physics you can still pull out a decent score if you have done your chemistry and biology well.

Hope this helped!