What would cause the temporal artery to dilate, cause mild headaches, especially when handled, and make for strong pulsating? Temporal Arteritis...

The most likely answer here would be nitroglycerin. It is absorbed via many routes, including transdermal, though it is most often taken under the tongue (sublingual). It has vasodilatory properties because it increases the amount of nitrous oxide in vascular endothelium, which causes a biochemical cascade leading to vasodilation. This effect is commonly taken advantage of in patients with stable angina, where nitroglycerin is used to decrease the workload of the heart, which is having...

The most likely answer here would be nitroglycerin. It is absorbed via many routes, including transdermal, though it is most often taken under the tongue (sublingual). It has vasodilatory properties because it increases the amount of nitrous oxide in vascular endothelium, which causes a biochemical cascade leading to vasodilation. This effect is commonly taken advantage of in patients with stable angina, where nitroglycerin is used to decrease the workload of the heart, which is having difficulty providing blood to itself. It would dilate the temporal artery, as well, as it would many other arteries. Finally, the side effect of headaches is well-documented. In fact, many patients who use nitroglycerin use the headache as confirmation that their medication is working effectively!