Hi Firefly, and welcome to WHL. I'm not a doctor, and haven't pretended to be one since I was 12, and know very little of lupus compared to the other members here, but... skin stuff can come from a reaction to anything, from what you eat, to what you wear, to the air you breath, or the meds you take, and also from disease. I used to get hives all the time, and then we figured out that I was allergic to shell fish. Bummer. You might start a food diary, and see if you can draw any lines. A food reaction can also cause joint inflammation and resultant pain. Take pictures of your rashes as you get them, and also as they progress, along with notes, and show them to the docs. We'll hope it isn't lupus, but rather something simple.
"There but for the grace of God, go I."
"... His mercy endureth for ever."