I've found something topical that seems to help me. Hypochlorous acid.
Don't let the name of it scare you off immediately. It's in all sorts of wound washes and even some eyelid washes. Concentration matters as to whether it is harmful, effective, etc.,. And if you research a bit, you'll see there are ways to make your own and control the concentration for a lot less $$ than the packaged medical washes. Just read ingredients carefully and avoid getting this stuff in your eyes or ingest it. It does degrade over time... there is a shelf life, so being able to make your own when needed is a real plus. And the stuff makes a great general cleaner too. It does smell bleachy, but no, it is not just bleach water.
Anyway, if I spray some HA on a Grover's spot, the spot goes away faster and with less itching. Spray it on and let it dry there. Don't wipe or rinse.
Gotta wonder if some sort of fungal infection is tagging along with my autoimmune Grover's, as HA is antifungal as well as antibacterial. I'm gonna try it on that one toe that's had an off-and-on fungal problem for decades.