I have the same thing on my front drivers side bumper. The dealer said they would have to repaint the bumper. The bubble/grain of sand is not noticeable but i did have the dealer note it in the "system" just in case it ends up flaking. I don't think some chimp I'm the back is gonna paint it as good as factory, so I'm leaving it alone.
2013 5.0, 6 speed manual, Brembo Pckg, 3.73 gears, American Thunder 40 series Flowmasters, 1 inch Lowering springs from Roush, J&M LCA, J&M Adj.Panhard bar, 20% Tint all around.