Fevers under 39.5C (103F) are generally not harmful in themselves. In many cases, fever is a good thing, as it is the body’s way of raising the temperature of the environment to be toxic to pathogens, bacteria, and viruses.  Fever usually does not cause harm, is self-limiting, and medication is usually not needed. Fever usually lasts no more than a few days. Infants under the age of 12 weeks with a fever of 38C (100.4F) or greater should go directly to emergency.  The main reason to treat a fever is to make your child more comfortable. But, if the fever is high (39.8C/103.6F or higher), you should consider treating it and seeking medical attention. Antipyretic (anti-fever) medications work on regulating the hypothalamus, the temperature centre in the brain. Both acetaminophen (Tylenol) and ibuprofen (e.g., Motrin, Advil) work well and should reduce the fever within 1.5 to 2 hours. If your feverish child is younger than 2, consult with your pediatrician before giving any medication.  Do not give children aspirin (ASA, acetylsalicylic acid). Children who take aspirin can fall ill with Reye syndrome, a life-threatening illness that causes swelling of the brain and other issues.  Always be sure to give the correct dosage to a child. Children do not take the same amount as adults. Dosages are based on age and weight so read the bottle carefully to determine the right dose for your child based on the bottle guidelines. Check with your doctor or pharmacist if you are uncertain how much to give.  There is no evidence that alternating medications reduces fever any quicker; rather, it can lead to dosage errors. This practice is not recommended in children.  Do not give ibuprofen to children younger than 6 months. If your child is vomiting or dehydrated, do not use ibuprofen. Take your child to a doctor if he has a high fever (over 40C or 104F) that does not come down to 38.3C (101F) to 38.9C (102F) with medication. Also take your child to the doctor if the fever lasts over 24 hours (for children younger than 2) or 3...

TL;DR in Chinese:
任由体温自行升降。 用药物降低体温，减轻不适。 如果不能将体温控制住，请前往医院寻求救治。 医生会诊断孩子是否为高热惊厥。