Same thing happened to me.
If you dont have any experience of what you are doing, I'd suggest that you dont open up you DS.
Unless you are very sure that you can replace the shell, dont do it.
Also, that flexible metal piece is probably the wires connecting the screens. Id suggest you protect it with your life.
but seriously. my DS's top screen became all white because it got bended or something from all the flip flopping around.
then I opened up my DS (phat), broke a few parts, then it died. I cried a little