Pega la vuelta is a dramatic and forceful Spanish idiom. While it literally translates to something like "hit the turn" or "stick the turn," it's a powerful command that means "turn around and leave," or more strongly, "get out and don't come back."
In this iconic break-up anthem, the singer uses this phrase to emphatically reject her ex-lover who has returned after a long absence. It's the core message of the song, packing a punch of finality and telling him to go back exactly the way he came.
This song is a full-on soap opera scene set to music! A man shows up at his ex-girlfriend's door after being gone for "Hace dos años y un día" [Two years and a day]. He explains he left "En busca de emociones" [In search of emotions] but discovered it was all "una gran fantasía" [a great fantasy]. Now he's back, realizing he wants the things he left behind with her.
She is not having it. At all. Instead of a happy reunion, he gets the door slammed in his face. She tells him it's too late because "ahora soy yo la que quiere estar sin ti" [now I'm the one who wants to be without you]. The chorus is a powerful list of commands for him to get lost: "vete, olvida mi nombre, mi cara, mi casa / Y pega la vuelta" [go, forget my name, my face, my house / And turn around]. She ends with a final, savage burn, telling him to forget everything, because "tú para eso tienes experiencia" [you have experience with that].