Apple Watch screen flickering in different colors and won't react

Today (of course shortly after my warranty ended) the screen of my Apple Watch went haywire and started flashing green, white and yellow and won’t respond (see picture below)...

Forced restart did not really help the problem. Once or twice after the restart the normal screen / watch application ran normally for a short while before the screen goes back into "disco mode" but most of the times after the restart it directly comes up flickering like below.

Anyone else run into this problem and has an idea how to solve it?

Thanks!