@witchercan, I have to agree with @strongbow that it sounds like a broken LCD. The screen assembly usually consists of multiple layers; generally there is a backlight layer, an LCD layer and on top a digitizer or touch screen layer. It is entirely possible and not at all uncommon for the LCD layer to get broken but leave the digitizer or front glass layer untouched.
Best thing to do is to add a picture of your screen to your question so we can see exactly what you're talking about.
[guide|21499|Adding images to an existing question - iFixit Repair Guide|new_window=true]