Can glitter get inside of screen

I don't think so. Remove the cover and use a soft brush to clean the device.

Depending of your iphone's model, check and clean also the charging port and/or the headphone port (this one only if you're iphone is a 6s or earlier).

Regards

Giulio

I have the same model, so there's no headphone port.

After gently cleaning the device, check carefully the charging (lightning) port and clean it.

If your iphone is charging normally, don't be worried.

Have a nice day.

Giulio

Forgot to tell you: check also the mute switch... on the left.

If you have a vacuum-cleaner (but not to much powerful, and keeping it far enough from your iP7), you can use it.

DO NOT use compressed air.

Giulio