no, I did not experience any worsening immediately following mercury removal. If the procedure is done correctly and you use some kind of binding agent before and after the procedure, there is absolutely nothing to worry about.
If you wait for yourself to get better before you have the mercury out, you might just be waiting forever. If mercury is causing you problems, why will you get better before removing it?
I don't see any reason why you couldn't rinse out with charcoal. I simply recommend ip6 because it's what I used and it worked great for me. But charcoal should work, as should any clay like bentonite.