Coleccionando heridas literally translates to "collecting wounds". This powerful and poetic phrase is the central metaphor of the song, and it's not something you hear every day.
KAROL G uses this expression to describe a painful pattern of repeated heartbreak. The verb coleccionar (to collect) is typically used for hobbies, so pairing it with heridas (wounds) creates a striking image of someone who has gathered so many emotional scars it's become a defining part of their life.
KAROL G opens this song with a huge question: "Será que el amor no es pa' mí?" [Maybe love isn't for me?]. She feels like she's always the one left alone, and it's become a habit to just gather emotional scars. She looks around and thinks that maybe real love belongs to another time, because today "Nadie quiere en estos días / Vivir como si no tuviera sentimientos" [Nobody these days wants / To live as if they didn't have feelings]. But she can't be like that. She admits, "Yo no tengo ese talento / Yo sí siento todavía" [I don't have that talent / I still feel].
Even though she's been hurt, she still wants to believe in love. She describes loneliness as her friend, "Tengo de amiga la soledad", and confesses that she couldn't bring herself to hate a past lover. She was told time heals everything, but for her, the suffering hasn't gone away. Despite all the pain and the sleepless nights, she holds on to a little bit of hope. But if it doesn't work out? She's accepted her fate: "Seguiré coleccionando heridas" [I'll keep collecting wounds].