Mel -

If you are running a high fever for any length of time, you need to be worked up ASAP by an internal medicine specialist. An "urgent care" facility at a good clinic or hospital is often a good place to start, if you can't get in to see anyone right away. There are many things it could be, but at least to the best of this layman's knowledge, RSD/CRPS is unlikely to be one of them.

Mike