hello thanks for consulting at hcm..firstly it could be traumatic ulcers, since it is not healing, r the teeth margins sharp?? if yes , get a coronoplasty done,, also use soft brush toclean the teeth, avoid traumatising the ulcr area,eat soft food,, avoid any trigger for
mouth ulcer to recur if u r noticing with certain food..kindly consult an oral medicine specialist at the earliest...hope it helps tc