Theres a drastic color change in my screen. (it's a drastic change in the rectangle) It stays and it goes. Sometimes I have to push lightly down on the screen to get rid of it. I tried to take a screenshot of it but it seems as if the glitch/ whatever it is, is internal. 

What can I do to try and fix this error??
Pressure on the display that changes the display contents indicates physical failure of the delicate connectors where the glass meets the metal wires running to the controller. 

I would have an Apple certified tech let you know if it’s safe and get a quote to fix it. Unless there’s damage elsewhere internally, that sort of failure doesn’t damage other parts or represent a shock / fire risk vast majority of the time so you could opt to not repair it if you don’t feel the cost or time out of service matter to you. 

This likely won’t get better or fix itself, though.