Restarting
If I change the region in my iPhone it will automatically restart; does that mean I will lose all my personal data? (Apps, photos, etc)?
Question marked as
No, a restart does not result in any data loss. HOWEVER, you should back up your phone regularly, and especially before making any changes or updates→How to back up your iPhone, iPad, and iPod touch - Apple Support. And it would be a really smart thing to enable automatic backups and leave the phone plugged in overnight so it will back up, unless you have nothing on your phone that it wouldn’t bother you if you lost it.