Get it checked as soon as possible. Say exactly what you just wrote and a medical professional should want to see you sooner rather than later. Today wouldn't be too soon. I just did a Google search of your symptoms exactly how you wrote it. Artificial intelligence said the following.

"Based on the symptoms you're describing, particularly the swelling and tenderness in your temples, the headache, and the visible bulging artery/vein, this sounds highly concerning for Giant Cell Arteritis (GCA), also known as Temporal Arteritis."