MacBook Pro 13" screen damage

New here!

I recently damaged my macbook pro, (my bed broke and fell on it) and there is a dent on the top case above the black plastic strip on the back.

here's the damage: http://a2.sphotos.ak.fbcdn.net/hpho...150266595579062_790369061_9492612_23291_n.jpg

My question is, is this damage to the LCD, or to the cables? sometimes the two sections either side of the strip of white return to normal for a short time, other times the white strip gets stripes of grey down it, and other times the screen goes black completely.

When the two stripes that are not white go back to normal, I can press on the screen where the "Macbook Pro" writing is, and they will return to their broken state, if that helps with a diagnosis.

It works fine with an external monitor, so it can't be damage to the graphics chip or motherboard... I hope :/

Any help is appreciated

If you are comfortable with opening the machine yourself then if you could post what year your MBP is or the specs of it then I can post a guide here for opening it, you can check the cables are seated properly and see of that helps. If the cables seem fine though it could unfortunately be the LCD.
As you mentioned if it works fine with an external monitot it would suggest that the GPU is in good working order.

Hope this helps

- Simon