iPhone wont turn on

Good day today i saw that my camera was not working so i decided to open up the device and try to reconect it well when i was finished the white screen of death appeared and would not go away when i press the home and power buttons it enters dfu mode but does not come back on a minute later i can see it turned on but the screen was black i took out the screen put it back in and got the same white screen and after a while, now it wont even turn on what could be the problem? I have tried everything maybe i need to change the battery? Thanks!