My Daughter Has A Sore On The Inside Of Her

my daughter has a sore on the inside of her lower lip. She has been slurping spit as it's been interfering with her ability to talk and salivate apparently. It's not a canker sore, bit its just a cluster of white tissue no bigger than 3 ball point pens and it's painful only when it's touched. Again, not a canker sore, no fever, no sport trauma etc, no rash, just one bump...