Hello there, you haven't mentioned that you are talking about which exam. So let's assume 1st for engineering. You can take a drop of second year. But you will have to problem during placement because many companies do not allow two year drop. So I will suggest you that second year drop for engineering won't be a good idea , as it can affect your placement but if you really want to become an engineer than go for it.

And now talking about second year drop for medicals than there is no problem study hard and appear for next neet exam and take admission in good medical college. I hope you got the answer

Good luck !!