Hello,
The ulcer will heal in a span of 5-10 days. Dologel will help with the pain, you can take
Vitamin B supplements to aid faster healing.
Stay hydrated
Avoid hot and spicy foods.
Health Tips
On other note, I can notice some calculus (hard yellow deposits) deposits around your teeth in the picture. This definetly requires a dentist visit for scaling /cleaning. This will maintain gum health and oral hygiene.