Temporal arteritis is an autoimmune inflammatory disease with an unknown cause (etiology). The condition causes inflammation and necrosis (death of tissue in the body) of the large and medium arteries (vasculitis) that branch from the external carotid artery on the neck. It is also called "giant cell arteritis" (GSA). The temporal artery under the surface of the head is most commonly affected during GSA, but any artery in the body can be affected (a systemic disease). Temporal arteritis manifest with a headache in the temporal region, a painful temporal artery, variable visual difficulties, pain in the jaw during mastication (chewing), and fever. Temporal arteritis is often accompanied by polymyalgia rheumatica (PMR). PMR is also an autoimmune inflammatory disease with an unknown etiology. PMR manifests with pain and stiffness of the shoulders, neck, arms, hips and buttocks. General symptoms such as febricity (fever), weakness, exhaustion ,and weight loss are usually present.
Diagnosis of temporal arteritis can be established if you have at least 3 of these 5 criteria, according to the American College of Rheumatology:
1. Are at least 50 years of age at disease onset
2. Are experiencing new onset or new type of localized pain in the head
3. Notice temporal artery abnormality (i.e., temporal artery tenderness to palpation or decreased pulsation unrelated to atherosclerosis of cervical arteries)
4. Sedimentation rate of greater than 40 mm in the first hour via the Westergren method
5. Temporal artery biopsy indicates vasculitis characterized by a predominance of mononuclear cell infiltration or granulomatous inflammation, usually with multinucleated giant cells
According to your data (“blood test high”) I suppose that your sedimentation rate and probably C-reactive protein were elevated. The only diagnostic procedure remaining is a biopsy of the temporal artery.