Reventar is a powerful verb meaning "to burst" or "to explode". It's a very visual and intense word, often used to describe something breaking under pressure.
In the song, Rauw Alejandro uses it to express extreme emotional pain, singing "Ahora me revientan to' los seso'" (Now my brains are exploding). This is a dramatic metaphor for the overwhelming jealousy and frustration he feels, making it a very memorable and expressive word to learn.
Puerto Rican singer Rauw Alejandro kicks off with a bitter truth: everybody says it is never too late, but right now he is at the very back of the line for his ex's heart ("Al final de la cola estoy / De tu corazón"). The spiral starts with social media. He spots her on BeReal holding someone else's hand, looking way too happy ("Pero con él se ve más grande tu sonrisa" [But with him, your smile looks bigger]). Seeing that photo sends his mind straight into obsessive jealousy. He asks who is making love to her in the car now, and who took her kisses: "¿Quién fue / El cabrón que me robó tus beso'?" (Cabrón is heavy Puerto Rican slang here for 'the jerk' or 'bastard' who stole her away).
He cannot stop looking at old photos and videos on his phone, keeping the device right beside him in bed just in case she calls. He even gets brutally petty about it. Sure, he admits the new guy might treat her better and make more sense for her life ("Yo sé que él es bueno y te conviene" [I know he's good and suits you]), but he still boasts that nobody matched their physical chemistry. She might laser off the tattoo of his name, but he is completely stuck. He begs her to teach him how to move on ("Dime cómo / Y lo hago, mi nena" [Tell me how, and I'll do it, baby]), because walking away on his own is clearly not working.