Hi KathrynDarby,
Thanks for reaching out to Microsoft Community and posting your inquiry. We appreciate the effort in providing a clear photo of the issue.
We suggest the following below to check if this is a hardware or a software issue:
• Restart the device and check if the discoloration is still happening.
• Check if the issue is also present on the UEFI environment.
The discoloration could be a hardware issue if it still happens on the UEFI environment, you may contact the Microsoft Surface Support team and check your options. If you're located outside the United States, you may check the issue with the Global Team.
If this answers your question, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.
Kind regards,
John Neil_J