Look at
www.lupus.org and read about
the 11 main symptoms of Lupus. Do you present with 4 or more of them?
Often plaquenil doesn't show any effect for 4-5 months as it builds up in your system. Are you feeling tired? Like your whole body has the flu? Sometimes Lupus feels like that and I'd expect your Dr to increase the prednisone.
Check out the Lyme's Forum hear at Healing Well - they will know more about
how Lyme presents than we do.
In general, I'd say get second opinions from two Drs, 1) a rheumy who is associated with your local chapter of lupus.org, and 2) a Lyme literate Dr who is associated with whatever Lyme organization there is.
Let us know how it goes!