My dr won't diagnose me, but my joint pain/stiffness, fatigue, dry eyes/mouth, rashes, raynauds & rashes improve on plaquenil (hydroxychloroquine). what does that mean?

See below: Plaquenil (hydroxychloroquine) has an anti-inflammatory effect on certain autoimmune diseases. Perhaps a visit to a rheumatologist to be worked up for possible rheumatoid arthritis/lupus/sjögren's syndrome/etc will determine a cause for your symptoms. Who prescribed Plaquenil (hydroxychloroquine) for you & for what condition?

Autoimmune disease: You probably have an autoimmune disease that does not meet criteria fully for diagnosis. With time, criteria may be met and a diagnosis may br given. If you are getting better with treatment, then a formal diagnosis is not critical.