Can you take a picture of what your describing and postbox back here in your thread @lewlew959
If there is visible damage at such an early stage of owning the phone then if this was my situation I'd take time and date stamped photo's of said damage and arrange to return the phone to get a new one.
These phones are not cheap so it's reasonable to have one supplied that is pristine out of the box.
For example I buy my phones direct from a Samsung Experience Store in the Uk and I always open it up in the store to inspect.
When I bought my Samsung Note 10+ 5G I opened it up and their was a very noticeable scratch on the screen.
Now this phone came with a factory fitted plastic screen protector so the screen itself may have not been damaged underneath, but I didn't want to remove the plastic screen protector to check until my Whitestone Dome Glass Screen Protector arrived so didn't want to have to return it then if the damage was underneath too and then try to explain it wasn't caused by me, and more importantly the phone I assume may have suffered some form of accidental damage to create the mark.
When I'm paying £1,000+ for a phone I wouod like it pristine out of the box. 
🌈 Stay Safe 🌈
