Secuelas translates to "aftermath" or "consequences," often in the same way English uses "sequelae" to talk about the after-effects of an illness or injury. It’s a powerful, dramatic word you don't hear every day.
In the song's title, "Secuelas de Amor," Carin León uses it to describe the lasting emotional scars and pain from a failed romance. He sings that what people see in him are the "secuelas de olvido" (the aftermath of being forgotten), a poetic and intense way to describe heartbreak.
Carin Leon does not hold back for a single second in "Secuelas De Amor." Right from the jump, he announces that he is not a fake person, so he feels zero guilt spitting out "Maldito tu amor / Mil veces maldito" ("Damn your love / A thousand times damn it"). This is not a sad song about missing an ex while crying into your pillow. It is a blast of pure, boiling regret over wasting time on someone who gave nothing back. He looks at his current battered emotional state and calls it out for what it is: "secuelas de olvido" ("aftermaths of forgetting"), the ugly scars left behind by badly matched affection.
What makes the track so fun to sing along to is how brutally honest Carin gets about looking foolish. He curses the sweet words he whispered in her ear and beats himself up for acting like a lovesick fool: "Quedar como menso de mano sudada" ("Ending up looking like an idiot with sweaty hands"). In Mexican slang, menso means a dummy or a fool, and the sweaty palms detail is delightfully petty; we have all been nervous around the wrong person and hated ourselves for it later. By the time he belts out "La oportunidad que hubo de ser feliz / Se la tiré al perro" ("The chance there was to be happy / I threw it to the dog"), he is completely done with romance. He wasted his shot at happiness on total nonsense, and he is mad enough to shout his own name right in the middle of it.