Small halo on photos iPhone 11

Hi,

I got some troubles with my camera. Apparently a little halo started appearing on the photos I take with my primary back camera. The issue isn’t present on the wide angle one, nor the selfie one. It started being annoying since it “moved” from the up right corner to almost the center. There’s no visible issue on the outside of the lens. Attaching some samples here. Pls help me.