is children is not usually a problem in and of itself. Rather, it is a symptom of something else going on, usually an infection. Most infections in children are not serious, as most are caused by viruses and will clear themselves up without treatment over a period of a few days.
You have already done the important thing, which is to take your children to see their pediatrician
. The pediatrician's job is to make sure the fever is not related to any serious problem that needs treatment, for example with antibiotics. Having ruled this out, the treatment of fever is just symptomatic. Making sure your children get plenty of rest and fluids is important. You can also give them acetaminophen or ibuprofen as directed to help lower the fever.
In general, it is best to avoid cold, cough, and flu medications in children. This is because they are not very effective and may have unwanted side effects. Therefore, I tend just to focus on rest and fluids and fever-lowering medicines.
If the fever does not start to clear up, or if your children develop any other concerning symptoms you should take them back to see their pediatrician.