Hasta los dientes literally translates to "up to the teeth". It's a classic Spanish idiom used to express that something is done to an extreme degree, similar to the English phrase "armed to the teeth".
In the song, Camila Cabello gives it a unique twist, singing "Me duelen hasta los dientes" (Even my teeth hurt). She uses this dramatic, over-the-top expression to describe the intense emotional pain her jealousy is causing, making it a powerful and unforgettable line.
Have you ever liked someone so much that their romantic history literally makes you sick? That is the exact brand of chaotic jealousy Camila Cabello and Maria Becerra are leaning into on "Hasta Los Dientes". Camila admits straight away that finding out about her crush's past knocks her out: "Hasta dormida te imagino con ella / Eso me enferma" [Even asleep I imagine you with her / That makes me sick]. She knows it is irrational—confessing "No es tu culpa lo que me haces sentir / Yo estoy loca, pero loca por ti" [It's not your fault what you make me feel / I am crazy, but crazy for you]—yet she still spirals into nightmares of seeing him with his ex.
The drama reaches its peak in the chorus with the title phrase: "No te quiero compartir, te quiero sólo pa' mí / ¿Me entiendes? Me duelen hasta los dientes" [I don't want to share you, I want you only for me / Do you understand me? Even my teeth hurt]. In Spanish, saying something hurts "hasta los dientes" is an exaggerated, physical way of saying the feeling runs right through to your bones; you are clenching so hard with frustration that your mouth aches. Maria Becerra matches that possessive energy when she pictures the ex watching them now, singing "Que sepa que ahora estás conmigo / No le pertenecen tus besos" [Let her know you are with me now / Your kisses don't belong to her]. It is messy, hilarious, and completely real about how bitter retroactive jealousy feels.