If a child with a cold and fever has a body temperature not exceeding 38℃, you can use warm water to wipe the child's armpits, abdomen, and groin to physically reduce the fever. Additionally, you can apply fever-reducing patches to the child and ensure timely hydration. Since children with fever can easily become dehydrated, it is important to replenish their fluids promptly, provide vitamins, and ensure they eat fresh vegetables and fruits.

If the child's body temperature exceeds 38℃, it is necessary to administer fever-reducing medication timely. If the child shows signs of poor mental state or recurrent fever, it is crucial to bring the child to the hospital for a complete blood count to further diagnose and treat the condition.