Background color turned red
It was normal all morning and when I just picked it up the background color turned red and I don’t know how to turn it back to normal.
iPhone XS, iOS 17
Try a forced restart: Force restart iPhone - Apple Support (Hold the third button press until you see the Apple logo appear, continuing to hold that third button press past any sliders that might appear.)
If you don’t have a backup, get one: How to back up your iPhone, iPad, and iPod touch - Apple Support
Then update to iOS 18 , too: Update iOS on iPhone - Apple Support