It can be recurrent aphthous stomatitis but cannot be confirmed without actually visualising. you should avoid spicy food and plan a visit to the dentist. Nothing to be worried about.

Hi, Recurrent aphthous stomatitis (RAS) is a common condition, restricted to the mouth, that typically starts in childhood or adolescence as recurrent small, round, or ovoid ulcers with circumscribed margins, positive family history of similar ulcers is common.. Identify and correct predisposing factors for recurrent aphthous stomatitis (RAS). brush atraumatically (eg, with a small-headed, soft toothbrush) and avoid eating particularly hard or sharp foods (eg, toast, potato crisps) and avoid other trauma to the oral mucosa. Any iron or vitamin deficiency should be corrected. If RAS fails to respond to local measures, systemic immunomodulators may be required.  Kindly consult Immunologist....