Tiredness is a symptom that can point to a range of different conditions, from infection to depression to anemia.
Anemia is a condition in which the red blood cell count is low, meaning that there isn’t enough oxygen getting around the body to the muscles and the brain. Therefore, the resulting effect is very similar.
The difference between anemia and high blood pressure though is that in the latter you still have the necessary red blood cells and the problem is instead simply with getting those blood cells to the necessary parts of the body.
Thus, the blood can become very red and engorged with oxygen while not moving properly through your system. And because the pressure is causing the blood to be forced to fill the veins, it will be pushed to the surface of the skin.
Combine these effects and the result is a very red complexion – as though you were hot after exercise.