It sounds like your LCD display was fractured. You need to replace it. I recommend buying the whole assembly as it is MUCH easier and looks much better, but it is significantly more expensive. You can just purchase the LCD by itself, but you will need advanced knowledge of electronic repair, tools, and patience. Here is a link to the part i recommend, keep in mind the parts are service provider specific. [http://www.ebay.com/itm/NEW-Samsung-Galaxy-S3-T999-i747-Tmobile-LCD-Touch-Digitizer-Screen-Frame-White-/151355589210?pt=US_Cell_Phone_Replacement_Parts_Tools&hash=item233d7f025a]