A phenomenon in which someone's head appears to be more narrow in size due to the head's owner experiencing an unpleasant surprise, a close call of some sort, long stretches of work or study, or an unacceptable amount of time without food in combination with the aforementioned criteria. The actual thin appearance of the head is not necessarily a measureable pathology and can often be considered a visual phenomenon associated with the person clearly displaying a lack of confidence, often accompanied by a confused or blank stare. It is essentially the opposite of being big-headed. The actual thin appearance of the head can be achieved through one single event or a series of events, each of which causes the head to become subsequently skinnier.
Matt had a major skinny head after working 50 hours last week while going to class.
John's car is really giving him a skinny head lately.
That near-accident on the freeway gave Bob a skinny head for the rest of the day.
Working through lunch always gives Eric a skinny head.
Rebecca's head got progressively skinnier as the day progressed.