Anita,
I noticed you're up there in De so the chilly weather change may be affecting your RSD like it's doing to mine. By coincidence I started a new med at the same time I was getting a bad head cold so it made me wonder if I was having a reaction or not. That could be true in your case too. Something to think about anyway.
As far as the possibility of your RSD spreading unfortunately that it could be. My neurologist told me that since I've had RSD over two years it's not a matter of will it spread but how much and how fast. In her dealings with RSD she found most cases lasting more than two years usually spread to some extent. The good news tho is if it does spread, it may not be a severe as the original area...