What is seen in the picture is rather this problem:
and not a flickering screen and according to the troubleshooting tool the next step after cleaning the contacts is to contact support with the following info:
Subject: "Coloured pixels image" Description: "My display presents a coloured pixels image. I confirm that my shipping address is correct. Please see attached the sample picture and advise how to proceed further." you order number your phone's IMEI1 attach one or two sample pictures in which the problem is clearly visible