The word fever means cold (remember the words fever and fever) but fever occurs when the body temperature rises again to 37 degrees Celsius. This means that as the temperature rises, so does the cold. It may seem a paradox to hear that cold occurs when the temperature rises.
Cold is not really caused by a rise or fall in body temperature. The body needs two conditions to feel cold. One is that the body temperature should be higher than the ambient temperature. The difference between these should increase. Even though the normal body temperature is 37 degrees Celsius, when the ambient temperature drops to 25 degrees Celsius (difference 12 ° C) we do not usually feel cold. Because we are used to it. But if this difference increases again, a large amount of heat is released from the body into the environment. This heat loss is the cause of the cold.