Its a dental abscess related to nearby tooth decay.

This is an infection. The decay in the underlying tooth is causing the infection. You go to the dentist only and preferably a pedodontist. They can guide you well and provide right treatment as well.

That's an abscess as the tooth decay has gone too deep. Please visit a pediatric dentist.

Hi! This is indeed a tooth infection that has advanced and involved the whole tooth! A Pediatric dentist will do the needful. Initially an xray will be taken and if possible root canal treatment will be performed and the tooth can be saved else if the tooth cannot be saved then dentist might advice to remove the tooth and place a space maintainer in that place. Either of the procedure will give minimal discomfort but will be the solution for this condition. There is a cavity in the front tooth also ( first tooth in the pic) Make sure you have a complete dental check up for your daughter so that the decay can be resolved at the initial stage itself.