I'd try popping it back out, don't just whack it in the center either, you need to shrink the metal back down, start working the edges first with a body hammer, light taps and a dolly [anvil] from the outside to hit against. You could even pad the dolly with a wash cloth. Just work slow, if it does not work for you nothing lost.
Eastwood makes a stud welder and dent puller for around $250 as does Harbor freight for cheaper, the puller with the harbor freight sucks.
Since I got my 13 sport I'm getting back into the practice of backing into parking spaces before I take a shopper out.