You could pop back to the shop and express your concern.
Emphasise that you bought a brand new camera because you like to keep your equipment pristine, therefore you like it to be pristine from the start.
They may offer a partial refund, store credit, accessory or whatever, or they may ask you how you'd like them to deal with it.
Make sure you know what you consider to be an acceptable solution before you go to the store, or you may end up regretting the agreed solution.
If it is bothering you, you need to contact the store ASAP, to reduce any suspicion that you may have caused it yourself.
It's difficult to tell from the photo, but does it look like a manufacturing flaw, or a scratch. If it's a manufacturing flaw (i.e. not correctly painted), then I would look at it as a unique indication that it's 'your' camera. If it's a scratch, then I would wonder how that happened to a brand new camera.
For what it's worth, I would just live with it if there are absolutely no other issues with it, but ultimately it's your call. Just act swiftly if you want to do something about it.