I noticed this when checking my tire air pressure.

 

that is just the inner mud shield, i wouldnt worry about it.

 

The screw with the big flat washer looks to be within its hole. The worn area looks like a tire (current or previous) was rubbing at full turn.

 

I was worried about the hole next to the screw with the big washer and the big gash to the right of it.

 

Don't be, it's not a critical piece. You can check to see if it's tire rub simply by turning the tire all the way to the right, place your hand back there to see if it's rubbing. Then do the same thing with the wheel turned all the way to the left.

If it's tire rub, smaller tires or a small lift kit will fix it. You can ignore it and it will "get worse" but again it's nothing to worry about. If there is no tire rub then you can just slap some black duct tape on it and call it good

 

Definitely tire rub. When the tire hits the fender liner and an obstacle, it's forcing the the liner to pull around the screw and open that secondary hole. Wrong off-set on wheel or needs a small lift kit ...

 

Good. Nothing is shiny. PO installed a 3" lift. Maybe this was prior to that.