Not much people have reported to use oral ivermectin without topical ivermectin. Interesting to read that it is somewhat effective.
Note that topical ivermectin can cause a breakout. So you may want to read Bad first reaction for advice to reduce it.
The environment in which you work may also play a role. At least in my situation things like sawdust and wearing things that pressurize the face (such as protection googles and masks) can cause breakouts.
Soolantra (topical ivermectin) can easily be worn in public, but I’m not sure if horse paste (topical ivermectin) is also that easy. But Sudocrem cannot be worn in public (at least not when you apply the amounts that I did).
You could also combine things with a moisturizer, like in Skin hydration & Moisturizers
Especially when you are working in a possible problematic environment, then hydration and protection of the skin may be extra important.