That looks like part of the mini LED array showing through.
Search online to locate and call contact your nearest, “local” Apple Store location to try/attempt to make an appointment to get your new iPad Pro diagnosed and options provided.
If you have had this iPad for less than 14-days, you can return this iPad to Apple for another brand new unit.
OR, failing that,
Contact Apple support via the contact support link located at the upper right hand corner of every Webpage of these Apple support communities.
Use the Hardware Repair and Device performance support categories.
OR
by installing and using the Apple Support app found in the iOS App Store.
Tap the iOS App Store link below.
https://apps.apple.com/us/app/apple-support/id1130498044
OR
Call contact Apple via the support numbers found in the link bekow.
Contact - How to Contact Us - Apple
Tap the link below.
https://www.apple.com/contact/
Best of Luck to You!