key, the connection to the screen may of come loose causing poor connection/disconnected pins. The link below(small tear down) can be used to show you how to access the screens cables to enable a reseat or to see if more damage exist. If not comfortable find a good computer/cell phone repair shop have them take a look, diagnose and estimate repair. Good luck.
I hope this helped you out, if so let me know by pressing the helpful button.
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