Regret
He didn't mean to do it. It had just slipped out, and before he knew it, the words were hanging in the air for all to hear. 'Mudblood.' That word that he despised, that word that he didn't mean but had used anyway. But Lily, she was going to hate him now and forever. She hated the word more than he did and he couldn't blame her. Things were heating up now after all, and there were whispers in the common room that He would soon be prowling among the Slytherins for recruits. If that happened he knew he would have no choice but to join. He owed his continued existence Lucius Malfoy, and Malfoy always called in his debts. And he, Severus, being the brilliant Potions and Dark Arts prodigy that he was, would be put forth as a candidate above the rest. And now he had sealed his fate. 'Mudblood.' And before he could scream out his apology for the whole school to hear she turned away. Lily. He barely noticed it when Potter used his own spell against him for the second time. It didn't matter anymore that she had told one of her friends about the spell. And maybe, just maybe, if he let Potter humiliate him a bit more, she would forgive him. Maybe. Hopefully. But…probably not.