Just take it easy, let it dry hard, then put the pickguard on and see what the finish looks like on the front after that.

I know from experience that it's basically impossible to sand back a burst so it looks right. You'll easily remove the single specs of dark paint, but where that paint is denser. it won't come off as easily and you end up with a hard paint line that doesn't look good.

If this were my build, I'd now concentrate more on darkening the edges of the body, maybe even switching to black, with quite a small feather area that follows the body outline quite closely.