My MacBook Pro display won't turn on

Summer 2012 MacBook Pro 15" Non-Retina. Purchased June 2013. NVIDIA GeForce GT 650M. Intel 2.6ghz Quad-Core i7.

Froze for some strange reason, so I held down the power button to force shutdown. Waited about 5 minutes and pressed to boot back up. I get the iconic chime, but I get a very dim bootscreen. Screen goes away and the keyboard backlight turns on. I can hear the fan going, so I know the computer is running. Screen never comes on. I plugged in my external monitor, thinking it will sort of reset the screen and such, and my extended desktop shows up on my external monitor, but still nothing on my MBP display. I can go closed-clamshell with my keyboard and mouse and everything works fine. Even the built in keyboard works fine. Everything works except for the display. I know it's not the video card or my external monitor wouldn't work.

Currently running time machine just incase.

Any ideas?