What is a blood vessel headache?

Not sure: One possible type of headache that could be described that way would be due to temporal arteritis, an inflammation of the artery in front of your ear. If you are having any loss of vision with the headache, see a doctor immediately. Another possibility might be a type of migraine. Both can be treated but need medical evaluation.

Headache: The most frightening of vascular headaches is subarachnoid hemorrhage from a ruptured cerebral aneurysm. This is often the "worst headache of your life" and needs emergency care. Migraines and other headaches are thought to be vascular in origin.