Since you didn't get a firm diagnosis on psoriasis, do the doctors have any other ideas, maybe some other tests? Does it seem like hives or go away with an antihistamine? Does it come and go? Maybe a food intolerance?
If it's possibly food, start keeping a food journal. If it comes and goes keep a journal and write everything you eat plus every environmental thing you contact. There are lots of threads on journals in the archives - search box at the top of the page.
You can ask any doctor, inc the allergist, to prescribe a Lyme test. It's just a blood test, and it would rule that out.
I never trust Dr. Google or forums, but if you google and look at pictures you might find something to consider. I found a skin condition that way (not related to yours). Try words like red round lesions or red circular rash, non-itchy ....... get some words from your search that describe your spots - like raised (if it is), or flat, or scaly ....