This New York Times article talks about how although fevers can be scary when it is happening to your child, most of the time it is a good sign that the immune system is working. It is a cause for concern in infants, but in general “fever is positive evidence of an active immune system.”
According to the article, fever does not harm the brain or the body despite misconceptions, though it does increase the need for fluids. And even untreated, fevers rarely rise higher than 104 or 105 degrees.
Make sure to stay hydrated!