Keep the appointments. It sounds like your dermatologist is on the right track. Good luck!
I know that MS(Multiple Sclerosis) and SLE(Lupus) can both cause those types of symptoms. Have you seen a Rheumatologist yet?
All the symptoms you have are common with Fibromyalgia. It is an awful thing to live with and makes you feel as if you're going crazy. I was diagnosed in 2005 and struggle with new symptoms all the time. Do some research on Fibromyalgia and my suggestion would be to see a Rheumatologist ASAP. Good Luck to you and God Bless!