This isn't a breakup song. It's a friendship betrayal where Swift refuses to name the actual crime, just the damage. The whole thing runs on accusation without evidence, which is the point: she wants the other person to feel guilty without having to specify what they did wrong.
Did you have to ruin / What was shiny? Now it's all rusted
The shift from 'shiny' to 'rusted' does the work of explanation without actually explaining anything. It's the sound of someone who knows what happened but won't say it out loud, banking on the other person's conscience to fill in the blank.
Still got scars on my back from your knife
The knife imagery puts the betrayal behind her, literally where she couldn't see it coming. But notice she's got enough distance now to craft elaborate metaphors about it, which contradicts the claim that the wounds are too fresh to heal.
Band-aids don't fix bullet holes / You say sorry just for show
This is the only moment Swift acknowledges an apology happened. The other person tried to make it right and she's saying the gesture was performative. Maybe it was. Or maybe no apology would have been enough because the real goal here is permanent unforgiveness.
If you love like that, blood runs cold
The switch from 'live' to 'love' in the bridge's closing line reframes the whole conflict. It's not just about what happened between them. It's a character assassination, saying this is how the other person treats everyone.
Swift has the distance to aestheticize the betrayal into a pop hook but claims she's too wounded to move on. The song wants it both ways: the moral high ground of the injured party and the satisfaction of never forgiving. What sticks is the refusal itself, the way 'bad blood' becomes a permanent state she's choosing to live in.