My iPhone 5s' screen is black and won't turn back on, how can I fix this?

I

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My iPhone 5s' screen is black and won't turn back on.

I tried to update an app, and when I did the phone turned black except for the top bar (time, battery, wifi) and I clicked the lock button and now the screen is only black. The phone vibrates when I charge it, and the phone vibrates when change the ringer from off to on. Please help!