Update (12/23/2017): you might have something wrong with the software and you can hard reset it. To do a hard reset, press and hold the power button (also known as the Sleep / Wake button) and the Home button (the circular button below the display) together for at least 10 seconds. On the iPhone 7 and 7 Plus, you perform a hard reset by pressing and holding the volume down button and the power button at the same time until the you see the Apple logo appear on the screen. If the Apple logo appears on the screen, there probably isn’t a problem with your iPhone’s hardware — it was a the software
I think it stuck. So use isopropyl alcohol. Drop a small amount of isopropyl alcohol onto the tip of a cotton swab. Press in the Home button as far as it goes and rub the alcohol around the edges. Press the button several times to work the alcohol into the cracks.