Uhhhh, I prooooobably wouldn't worry too much about it, but I would worry. I don't know if I should be putting sulfer into my bloodstream (by smoking it). Imagine striking a match, then while it's just starting to burn and burning the brightest, sucking in that smoke, but a whole bunch of it and not just one match.

I imagine that overall rhizome is correct, depending on what you mean by "almost ready for harvest". I suppose that over time that shit might dissapate somehow and be less harmeful or even not harmful. But if you are harvesting 3 days after spraying that, I migh be a little concerned and try to wash my bud with some cleansing thing. I know that this way I will loose more trichomes than is ideal, but at least it might help give me a false sense of security.

At the very least I would do a little web search on the effects of sulfer.

Oops. My first result in a search:

The damaging effects of sulfur with animals are mostly brain damage, through malfunctioning of the hypothalamus, and damage to the nervous system.

Wanna read more from that article?

Sulphur (S) - Chemical properties, Health and Environmental effects

I really hope this is going to end up OK for you, but if it were me I might dig just a but deeper before smoking, especially looking up how long sulpher can last in open air, sitting on a plant.