13in MacBook Pro Retina display issue

I have a 2012 13in MacBook Pro retina. Yesterday I was watching YouTube and the display blacked out for a few seconds and came back to it with pixels glitching and individual ones flickering colors. They the display started glitching and the picture was jumping around before it completely went out. Now it boots to black, flashes and stays a backlit black. There is a chime. The keyboard doesn't light up but the green caps light comes on. The Apple lights up and stays on even if you close the laptop. I tried linking it to another display via HDMI and it recognizes a display but the external display displays the same black screen. I tried shift-pwr option-control-p-r and all those. I do have an Apple appoint but I'm just curious if anyone knows what may work or can determine what the issue is. I'm out of warranty and want to know what I'm lookin at before I get to Apple