What is causing this sharp shooting pain in the jaw?

Michael, 50, has severe, left-sided lower jaw pain near the molars. 

MRI fiesta sequence

He had a previous episode for four weeks several years ago and was treated with dental extractions. 

The pain returned two weeks ago and is repetitive, sharp and almost constant. 

It lasts seconds at a time and has a trigger point over the lower molars. It is worse with eating and brushing his teeth, and cold foods and air conditioning on his face. 

MRI brain shows a vessel loop in the vicinity of the left