I don't remember the timing, but my really bad case seemed to take ages to clear up. 10 days total? Two weeks? Soon after that I had another exposure, and that time I used the Zanfel early on and I think it resolved quickly (2 days?).

It's probably very individual. Someone in my family doesn't react at all to it, so my guess is that even among those of us who are affected there's probably a range of reactions and timelines.