iPhone 11. Dark spot underneath, doesn't affect screen

I bought my iPhone 11, 4 days ago, and just today I realized that there's a dark spot that doesn't go away, and it doesn´t affect the screen. When the screen is turned on, it looks ok, but when turned off, you can see that spot (see picture). The phone has not been dropped or wet. I have barely use it. What is this and can I ask for a new one?