Screen went black in the middle of a call - phone still worked

[dmaxdmax]

iPhone 6 - 96% battery life - iOS 8.0.2

I called a doctor's office, listened to the menu, and when I went to select "2" the screen was black. Hitting the home button did nothing nor the volume buttons nor shaking it. I don't think I got to the power button before the operator picked up. The voice worked fine but when the call was done the screen was still black. At that point I hit the home button and it came up to the lock screen.

Any ideas?

 

[greytmom]

Perhaps something funky with the proximity sensor (the thing that makes screen go black when raised to your face during a call). If it happens again, talk to Apple.