I very rarely ever get diaper rash. If I do, usually Desitin overnight and it is gone.
Lately I have had a severe itch that has lasted for several weeks. It gets better, but then it comes back. I tried Desitin, I tried just baby powder, I tried baby lotion, all had some relief, but the itching always came back with a vengeance.
I finally soaked a couple of Kleenexes in hydrogen peroxide and applied them to the area. It took two days but the problem appears to be gone. If that ever reoccurs, I may have found a very inexpensive solution.