Don't worry!
As I did remember my girl a few times go to hospital when she had serious fever and I also worry about that. At the end, it normally caused by Virus and it will keep 4-5days high temp and then will drop it slowly. Keep to take her/him shower with warm water and drink somemore warm water. She/he will get well soon!
don't worry,fever will last for 4-5days, somtimes 1 week, u just check the temperature regularly, give the medication as prescribed, give water/fluid small & frequently,bath with warm water.Don't worry, caused by virus is like that,alway high fever esp at midnight.take care!