Thanks for sharing your concern.
your history suggests that you have developed apthous ulcer on your palate.
This could be due to many reasons like vitamin B deficiency
,stress,smoking.poor oral hygiene
to any food stuff or rarely an abscess
can also cause such symptoms.
Therfore please start vitamin B capsules and continue them for 15 days.
Apply dologel locally before and after food for pain relief.
Avoid hot spicy and hard food stuff.
Take healthy and nutritious diet and also drink plenty of fluids.
If the symptoms do not recover within three to five days please visit your dentist
and get it examined clinically.
Hope it helps.