How does the child have a fever of unknown reason 39 degrees to do

The child has a fever of 39 degrees, which is already a high fever. You should give the child a physical cooling in time and let the child take antipyretic drugs. If the temperature cannot return to normal, you should take the child to see a doctor as soon as possible and follow the doctor's advice to inject antipyretic treatment, so as not to affect the child's nervous development.