You are doing the right thing by getting an appointment with a dermatologist. Does anything seem to help? You say the bumps come and go. Is there any pattern to when they appear or go away? You may want to keep a log or even take a photo of the rash to bring in just in case it goes away before you get to see the doctor.
Here is an article I wrote on Unexplained Skin Rashes that might help you in the interim before your appointment.
Please let us know how things work out for you.
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