I always use protective cases, including onde prevent the camera from touching surfaces.
Well, something contacted the lens surfaces. This look like chips in the glass to me. If the case did not protect the camera lenses (seems the issue here) then you may have a claim against the maker of the case.
NOTE: No one "paints" camera lenses. They may have a micro-thin anti-reflection and color-correction coating that is applied by plasma-phase deposition, but what I see looks far deeper than the almost immeasurable thinness of an optical coating.
If I subscribe to AppleCare+, will it cover cosmetic damage like mine ?
Unlikely. My understanding is that, if you do not bundle AppleCare + with the purchase of the device but you are in the 60-day grace period, Apple can reserve the right to physically inspect the device for pre-existing damage.