Eat lot of fruits & green leafy vegetables & drink plenty of water. Increase dietary intake of vitamin B, folic
acid, iron and use of vitamin supplements etc
We need more investigations with clinical examination to decide upon treatment. You may need Coronoplasty (smoothen teeth edges) along with Multivitamin cap, for five days in the morning after meals & antiseptic ointment or gel on the area of ulcer
until then. Mouth sores
are common and rarely cause complications.