Welcome Tina sorry to hear your have discoid lupus. You'll find a lot of great folks here. We don't have a lot that post who have discoid lupus, most of us have SLE which is systemic but we certainly understand the ups and downs of this disease.
Staying out of the sun is really hard for some people. You need to make sure you wear the highest protection of sunscreen, there is clothing sold that has UVA protection in the clothing. Wearing sun hats help, stay out of the sun during the peak of the day. If, I go outside to sit it's usually in the early evening like around 5 to 6 pm. I normally sit under our maple tree in the front yard.
I normally, don't sit outside though during the summer. It's way to hot and humid here where I live. My lupus has affected my lungs and humidity affects my ability to breath a lot. I'm on oxygen 24/7 anyway, once I'm outside in 80 degree weather with more than 45% humidity I have to turn up my oxygen by at least 2 to 3 liters more.
Avoiding stress with help with your lupus. It will lessen the amount of flares you have and if you Dr. prescribes plaquenil for you it should be fully helping you within 6 months. I'm sorry to hear that your sister also has lupus. Keep coming to the forum and ask any questions you have. Someone is always around to answer questions. Again, welcome and you'll enjoy it here.
DX- RA, Lupus, Fibro, LGL Leukemia, Pulmonary Hypertension, Bells Palsy, Gastroparsis, Blood Clots, Cateracts, Glaucoma, Chronic Pericarditis & Pleurisy, Severe Anemia. Way to many medications to list.