I would like to know if you have had any incidence of trauma previously? If not and its an infection by itself then the reason can be the position of the tooth is such that there is constant trauma to it by your lower tooth which has lead to such a bone loss and infection or it could be an infection of the supporting tooth structures by inadequate brushing in that region without any trauma. In either case if adequate support is remaining then the tooth can be saved though if trauma is present you will need to get tooth position correct by braces and only then any gum surgery would help. The bone wont grow back but bone grafts can be added to support your tooth which again would depend on the condition of the tooth which can be seen by your dentist. Though if you are told that the support is such that it has to be removed then at such a young age you can go for a dental implant immediately to restore that tooth which good esthetic results which will be as good as your lost tooth. But be sure to brush right and prevent any such thing further. Take care.