Maldito literally translates to 'damned' or 'cursed'. It's a powerful and dramatic word used to express intense self-criticism and regret.
In the song, the singer desperately exclaims, "Soy un maldito" (I'm a wretch), admitting he has done something terribly wrong. This raw confession captures his desperation as he stands outside his lover's window, begging for forgiveness in this intense musical confrontation.
This song is a whole soap opera in three minutes! It's a late-night argument set to a dance beat. A guy shows up at his ex's house at three in the morning, singing outside her window: "Son las tres de la mañana / Y estoy en tu ventana" (It's three in the morning / And I'm at your window). He's begging her to listen and come out so he can explain what happened.
She is not impressed. At all. Her response is basically, "¿Y tu qué estas pensando / Llegando aquí tomando?" (And what are you thinking / Showing up here drunk?). She tells him to go away and let her sleep. He gets more desperate, admitting he's a jerk, "Soy un maldito" (I'm a damned man), and promising he'll do anything she wants if she'll just forgive him. It's a classic, over-the-top plea for a second chance.