I bit my lip in my sleep and it bled a little. now there's a lump that resembles a blister but isn't painful and has no pus. what could it be?

A blood blister.: A small amount of blood bled into the outer layer of the tongue causing a blister. As long as their is no pain nor pus, it will resolve within a few days.

Mucocele: Sometimes trauma to the oral mucosa can cause you a small cyst like structure underneath. If it is small and not bothersome, continue to observe it. If it grows or causes discomfort, see an ent.

Mucocele: It sounds like a mucocele where the duct of the minor salivary gland is blocked and not allowing saliva from the gland to flow.

Mucocele: You may have ruptured a minor salivary gland or duct that cause salivary deposit into your lip soft tissue called mucocele. Consult with your dentist to have it removed. It can be removed very easily in the dental office.