Hi, is it only on one side or both sides. You could check with a dentist for any cavities, or It could be due to transient infection of the oral cavity/ tonsils which will settle on its own. If it's persistent you will need a course of antibiotics and if still it's not settling you will need an examination of the node through an fnac procedure ( where some sample is taken through a needle ) or an excision.
Next Steps
Do follow up if it's persistently there