Musnad Ahmad 30:1276

Muhammad ibn Bishr narrated to us, Muhammad ibn ‘Amr narrated to us, Abu Salamah narrated to us, from Abu Hurairah, who said: A Bedouin entered upon the Messenger of Allah, may Allah bless him and grant him peace, and the Messenger of Allah, may Allah bless him and grant him peace, said to him: "Has Umm Mildam ever seized you?" He said: "And what is Umm Mildam?" He said: "A heat that exists between the skin and the flesh." He said: "I have never experienced this at all." He said: "Has a headache ever seized you?" He said: "And what is a headache?" He said: "Veins that throb against a person in his head." He said: "I have never experienced this at all." He said: So when he turned away, he said: "Whoever would like to look at a man from the people of the Fire, then let him look at this one."