Are there any fixes that can be done without replacing the full bumper or taking it into a body shop?
Sorry to say that's pretty bad - you've lost not just the clear coat (lacquer) but the actual paint as well.
The good news is that because it's on the bumper (which is plastic) you aren't at any risk of rust as a result, it just looks awful. The bad news is that there's no easy DIY fix that's going to look much better. That's going to need spraying at a proper body shop I'm afraid - on the upside it doesn't look like it's going to need blending so it's just a blow over on the bumper itself so it shouldn't be ruinously expensive.