how to turn on proximity sensor for iphone 7 plus
Everytime I lift my phone up to my ear the proximity sensor doesn’t do its job so I’m always hitting buttons with my cheek and it’s frustrating
There's not a way to disable/enable the proximity sensor.
Have you tried restarting your iPhone? Restart your iPhone, iPad, or iPod touch - Apple Support
Have you tried restoring from a backup? Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
Have you tried restoring to factory settings? Restore your iPhone, iPad, or iPod to factory settings - Apple Support
If you've tried all these things then make an appointment at an Apple Store to have the device tested and they can tell you what your options are.