Went from 200+ fps to permanently below 50 after laptop got very hot

So the other day I fell asleep after using my laptop but forgot to close the game I was running (minecraft) before I fell asleep. I was on my bed using it so anyone who has a gaming laptop will know that they get no air filtering through when on a bed/blanket, so when I woke up the thing was really hot. After waking up I turned if off and didn't use it till the next day. No every time I play I can barely get 50 fps, which I know may be perfectly fine for some people, but going from 200 to 50 permanently means something has gone wrong and I want to try to reverse it, so please if anyone could help that'd be great!

With no clue which "laptop" you damaged, a guess is one with two video systems. One is the dedicated video chip on motherboard that runs games very fast. That has failed. Now you are using the integrated video system that is part of the CPU. That runs games a lot more slowly.
That is all that can be guessed from only "laptop" and no maker, model number, age, warranty status, or operating system. See maker customer support or a repair shop.

Yes I will tell you what happened and you're not going to like it when you blocked the fan inside the temperature Rose to high and the CPU has cooked itself and or if you're very very lucky the hard drive simply overheated and your hard drive is now damaged and the platter is turning very slowly I sure hope that's all it is is a damaged hard drive because if the CPU got toasted your computer is pretty much good for a paperweight