Why does the watch's face turn red?

On which Apple Watch Model? If Apple Watch Ultra, turning the digital crown turns forward turns the watch face red and turning it the opposite direction back returns to the standard color you have selected. This is what is called Night Mode for Apple Watch Ultra.

Hi Budrauth,

Thanks for using the Apple Support Communities.

We need help understanding the type of support that you're seeking.

When you have a free moment, please provide us with more information regarding the exact issue you're experiencing with your Apple Watch and what you'd like to accomplish, and we'll do our best to help you find a solution. 

In the meantime, check out the link below to see if you find it helpful.

If your Apple Watch won't charge or it won't turn on - Apple Support

If the resource above has nothing to do with the type of support you're seeking, provide us specifics on what you are seeing and experiencing on your end for more help, and we'll continue from there.

Cheers!