Hi, 

To be eligible for a medical seat through NEET you need to have a minimum qualifying marks.

For OBC according to last year the qualifying score was 40th percentile of the highest neet score i.e 96 marks.

A score above that would qualify you for neet counselling. However only qualifying won't guarentee you a seat.

With a score of 420-450 its difficult to get a government seat through 15% AIQ counselling.

You might have a chance in certain states provided you have the state domicile. But since you haven't mentioned your state its difficult to guide in that direction accurately. 

You might also have a chance if u apply for private medical colleges in some states lik UP etc. 

Theres the option for opting for deemed universities too. You can a have a fair chance there.

Having said this, these probabilities are on the basis of the cutoffs of last year. The cutoffs tend to vary each year depending on several factors like number of candidates, difficulty of paper etc. 

I shall share below a link which might be of help:

https://medicine.careers360.com/neet-college-predictor