Q: apple watch series 2 green screen

Had my Apple Watch Series 2 (42mm black) delivered yesterday.  Been working fine until 5mins ago.  Looked at it for the time and it has a green screen with black lines across it.  I've tried a reset (hold crown and side button 10 secs) and tried reset via phone. Still same green screen.  Only goes away when back light goes off to black (sleep/off) screen.

Any ideas?

Thanks