Fevers spike when an ill person is at rest. The body can heal faster and better while at rest. The fever is good, it needs to break, that is when whatever caused the illness is now killed because of the high temp. Taking Tylenol and other fever reducers only prolong the fever to spike.
Fevers spike at night with EVERYONE. A child’s temp can go scary high, keep her hydrated and give her tylenol as needed.