Due to biting something hard may too cause such thing so apply dologel n let it heal if not getting better visit a dentist

Let’s not think of anything extreme . It may be cause of some irritation or you would have eaten some crunchy food or accidentally poked there . They take a while to heal . Avoid spicy or hot food till it heals cause they aggravate the pain . You can use oral pain relief gel over that area . If it increase please visit a dentist for clinical examination .Don’t worry . Take care