One of the most common symptoms of Lupus is the butterfly rash which can extend from the cheek, over the bridge of the nose to the other cheek. This rash can, sometimes, be red and raised and can often worsen when we are in a flare up.
I cannot tell you if your rash is, indeed, a lupus rash. The fact that it appeared after physical exertion would make it very difficult to give you an definite answer. If the redness does not dissipate, I would suggest that you contact your doctor. Especially if you begin to notice other symptoms that might indicate a flare up.
Best of Luck
Peace and Blessings