Hello, A mouth ulcer generally takes 7days to heal so only thing that you can do is make the course pain free during eating for this you can apply any anaesthetic gel like mucopain at the ulcer site when you are eating . You can take some b complex capsule for 15 days , once a day . The ulcer will take its own sweet time to heal just let it not get irritated by constantly stretching the area by seeing it again and again or by touching the site .