It is unlikely for the allergic manifestation to the vaccination (even if we assume that you are allergic to the vaccine) to manifest after the fourth dose. Also a localised swelling at a location distant to the site of injection is another impracticality, although it cannot be completely ruled out. It could be a traumatic injury to the lower lip while biting or some other etiology causing this swelling which needs to be evaluated by a proper clinical examination. The right treatment can be suggested after the proper diagnosis has been made. Regards.