Laptop screen gets darker

My laptop started doing this relatively recently. I bought it in September of 2018 and nnever had this problem before. After a while of working on it, the screen just gets darker and what appears to be spotlights appear on the bottom of the screen. I am attaching a picture where you can see exactly what is wrong with it. I don't know what to do. When I restart it, it goes away but not for a long time. The screen brightness is at the highest point but it is significantly darker than what it usually is.