Thanks for using Health care Magic. Read your query. In your query you have not mentioned if any of your child s in that area are decayed or does she has any history of pain/trauma in that region. By the complaint described, it can be a abscess related to any of the tooth which will require an thorough examination by the dentist . She may also require a dose of antibiotics . I would advice you to visit a pedodontist and get it checked as soon as possible and get the needed treatment done. Hope this was helpful. Thanks and regards.