I've heard of that sensation before. Someone said that it was an indicator of mercury being literally pulled out. Certainly, it'll be doing something for sure. I had symptoms also (even when i had the good experience) and it got so bad I had to stop (i only took it for oneday), but the good effects still happened afterwards anyway. They didn't last too long, but showed it had temporarily given me an idea of how it must feel to really be normal.

I had used it that time with DMSA though and I think that helped.