A lip bumper is an appliance used to create space and anchorage, mainly in the lower jaw. It is made of thick wire shaped like the dental arch, and its curved front section is covered with plastic so that it is comfortable for the lip. It is prescribed for children to create space for the lower side teeth to come through, by holding the back teeth (the first permanent molars, or ‘sixes’) in place or pushing them backwards. It uses the force of the lower lip muscle, which presses on the appliance and gives it a backward force. It can also be fitted in the upper jaw, but then it relies on the pressure of the upper lip, which is considerably weaker. This appliance is worn for 12–14 hours a day and gains 1–2 mm of space in the dental arch.
This answer is for general information. Your own case needs an examination by an orthodontist.