Hello sir,
The main cause of mouth ulcers is trauma from hard food stuff.
other reasons include Stress, poor oral hygiene, deficiency of
vitamin B-12 or iron.
you can use an antimicrobial mouthwash like chlorhexidine and apply ointment topically like orajel ,mucopain or Anbesol 2-3 times a day.
Next Steps
If ulcer does not disappear in 2 weeks then visit your dentist for further consultation.
Health Tips
Avoid hot, oily and spicy food.