Swollen lump under tongue

My daughter (13 yrs) has been complaining of a swollen lump under her tongue about 1" long by 1/4 " ..... about three days later she now has come down with sore throat and fever, and still has the lump.  In addition to that, she says the "walls" or inside cheek parts to her mouth feel like they are cut or maybe a bad burning feeling, though there is no redness or visual indications of anything?

I'm thinking the sore throat & fever are non related to this bizzare mouth issue.  but her mouth is the most bothersome.

please help? point me in the right direction? MD or Dentist?