I bit my boyfriends lip really hard and theres a lump now?

Probably bled. More than likely you caused bleeding inside the lip, and this formed a fibrous clot that now feels like a lump. If that, it will, slowly resorb. But it could be more serious like an infection/abscess, that may need antibiotic and surgical drainage/removal. A human bite is the dirtiest and most dangerous in the animal kingdom. Is he still ur boyfriend? Young woman, never do that again (or, guy, run).