How can I have a fever quickly?

The doctor replied:

it can give off fever quickly. Only when it destroys its own immune system and virus or bacteria invade the body to cause infection, can the pathogen form a heat source and affect the thermoregulation center, can it give off fever. It can take cold to inhibit its own immunity and make the pathogen invade to prevent its fever. This kind of behavior is easy to cause serious physical injury. If there is a serious infection, it can lead to septic shock or life-threatening phenomena. Therefore, this anti normal method is not recommended.