A young man has fever and fills cold within but is temperature is hot and he's feverish ?

The hypothalamus contains the body's thermostat, this senses the temperature of our blood. If fever develops, the body responds to the infection and sends a signal to the hypothalamus to raise the set point to a higher temperature. This will make the hypothalamus to assume that the person is too cold, for the body temp is lower than the set point. This is why the person feels cold. Our body has a capability to regulate the body temp, so this will result in increase in temp, and will make the hypothalamus assume that the person is fine now, so he won't feel cold. The set point will return to normal if fever is gone.