welcome to HCM
Thanks for the query
i think this could be an allegic stomatitis
leading to these symptoms. this usually happens due to allegy some kind of medicine or foods or change of tooth paste recently. so theses things have to be ruled out first by detailed history and if necessary an allergen testing and then keeping away that particular allergen will be the remedy.
some times it can also happen due to vitamin deficiency
, which can be treated by vitamin supplements.
so its better to consult the dentist
for diagnosis, then followed by treatment strategy.
hope i have tried to anwer your query.