My 5 year old's gums have been bothering him. He complains that his teeth hurt. We took him to the dentist & had his mouth x-rayed & the dentist said he doesn't see anything wrong. Along with the swollen gums, his breath is awful, he has one cold sore on his bottom lip, & for the last 3 days, he had been running a fever. I believe it's gingivitis, but am unsure & in desperately need of help.