Bórrate is a strong command form of the verb borrar (to erase) combined with the reflexive pronoun te (yourself). Literally, it means "erase yourself," but it's often used more figuratively to tell someone to disappear or get lost.
In this emotional song, Christian Nodal tells his ex, "Bórrate mi nombre de tu cuerpo y alma" (Erase my name from your body and soul). He uses this powerful command to demand that she completely remove any trace of him from her life, highlighting his deep pain and desire to move on.
Christian Nodal throws all polite break-up etiquette out the window in "Quédate". The title literally means "Stay", but he quickly twists that plea into a bitter punchline: "Quédate, pero muy lejos" ("Stay, but very far away"). He admits right off the bat that this relationship brought out his absolute worst ("Tú sacaste la peor versión de mí" ["You brought out the worst version of me"]). While he tells onlookers that he learned a valuable life lesson just to save face ("Pa' quedar bien con la gente" ["To look good in front of people"]), he confesses to us that the whole experience was completely useless.
He pokes fun at her ego too, calling her "peor que la fama" ("worse than fame") because she wanted to get back together, but only if he begged for it. Instead of begging, he promises to act like a gentleman ("como un caballero") and keep her secrets safe, on one strict condition: she needs to stop stepping on his pain ("si no pisas mi dolor"). He is rebuilding his self-worth piece by piece, noting that right now, barely his own reflection in the mirror feels any love ("apenas el reflejo de mi espejo siente amor").