Hello and Welcome to Android Central Forums .....I believe it's a hardware issue...still you can go ahead and diagnose the screen in your device using hidden diagnostic menu ..Enable Developer options in device settings...
To access the hidden diagnostic menu on your Galaxy S6 edge, simply open the stock Dialer app and key in *#0*#.
As soon as you key in this code, the diagnostic menu will automatically appear on your Galaxy S6. You can tap on the different options in the menu to test different components of your handset..if you encounter anomalies even there ,a hardware fault might be triggering it..!!
As the device is just a week old ,it must be covered under the warranty .In that case i would suggest you ...try to get a replacement....or the display changed...!!
REGARDS...!!