What Causes Painful Knees Along With Bilateral Mottling Of My Legs?

Hello. I am a 42 y/o RN and take very good care of myself. My physician has been testing me for Lupus for 5 years now. Sed rate, CRP, FANA, and rheumatoid all negative/normal. My symptoms started with discoloration in my knees not related to trauma, severe sudden onset knee pain and bilateral mottling of my legs. My symptoms seem to come and go and vary in severity jumping from joint to joint worse in my knees, hips, ankles and hands with muscle pain between my hips and knees. The flares usually last 6 to 8 weeks and may disappear for months. I do not have the classic butterfly rash but I do feel flushed often. My mother and older have a positive rheumatoid factor and my younger sister has psoriatic arthritic. The last few months I ve noticed what appears to be cream colored painless nodules on my labia. They resemble acne but are hard. I have had a vaginal hysterectomy with an a & p repair so there has been a history of trauma to the perineum. Could this be a sign of lupus? Living in pain without a diagnosis is very frustrating.