My daughter has lupus and also has had blood clots. You have to listen to your body, you know your body better than anyone else. If you are worried I would not wait because you will just make yourself feel worst by worrying. It could be a blood clot, or something else . Its best to be safe then sorry. you would think if it was your lupus both legs would be swollen. Did you try and put your foot up and put a heating pad or hot water bottle on it? My daughter is in a very bad flare right now and both her legs and feet were badly swollen (which she had checked out but just inflammation not her kidneys or blood clots) I hope you can get this taken care of I know its no fun having all these problems and this nasty lupus.... I wish you the best of luck, and maybe someone else with lupus will be of better help. My prays or with you.. :blush: