The answer in general would be fat grafting to the lips. If the soft tissue is contracting around the lip, that would not be helped, but to give some volume to the lips themselves fat grafting would be worth looking into. An in person evalution by a board certified plastic surgeon with...
After trauma, the bump maybe cause by either excesses scar tissue or a mucocele. A mucocele is a cyst caused by entrapment of a mucous gland that isn't properly draining. This could've been caused by the trauma that you received to the lip. The scar tissue or the mucocele could be...