I and my fellow field biologists have never had a negative reaction to sulfur - but you might be sensitive, and this is not medical advice, etc. It works by slowly reacting to moisture and creating a toxic cloud of hydrogen sulfide near the skin which drives all arthropods away (even makes "seed ticks" - ie groups of freshly hatched ticks - jump off your skin if you already have them on you). In the past I could get "sublimed sulfur" or "flowers of sulfur" at pharmacies, but as it got hard to find I bought a large almost lifetime supply. Now I would look at one of these:
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dh...
(perhaps the Humco in particular). I create a powder puff from some powder in a sock which I keep in zip lock bag. Then I can knock the puff against socks, pants and skin.
The downside is that if you do this often and you wash your socks with your shirts, I have found that there are dance partners that can pick up a whiff of brimstone (not terrible but a little off putting).