How Can Fever, Poor Appetite, Odor, Lip And Gums Swelling Be Treated?

my son is 3 he recently was feeling bad (3 days ago), running a fever and poor appetite. yesterday when he woke up i noticed that his lip looked swollen when i checked, his gums were really red and swollen and his breath did not smell very well. I figured it was from him not brushing his teeth while he was sick, so i had him gargle some mouth wash. that night he had trouble eating so i gave him some orajel. This morning he has these yellow spots on his gums, his lip is still swollen and his breath still smells. Is there something that i can do here at home to make it go away.