Why is my NDSI touchscreen looks distorted?

I just grab my NDSI from my old box where i keep my things inside. The last time i use it is around 2-3 years ago. When i check it, the touchscreen looks like this:

The screen looks distorted, the color looks like a negative effect, and in some game scene it'll flickering. I remember when i was younger before i left the dsi, i used to open the Shell and take a look at the inside (i know it sound dumb. Curiousity just driven me, haha). And when i close the Shell, i accidentally take off the screen ribbon. Then i gently put it in the place. I'm not sure if i might tear it or break it, or maybe it just loosen up.... After close the Shell it used to looks fine, i experience this just by now. What do you guys think?