Do not wipe with a rag as this will spread the oils. Rinse, rinse, rinse. Steroids do help stop the spread of the rash. As later symptoms appear, it seems that anything that will reduce the itching and cool the skin, helps. Cooling the skin reduces oozing, as cool vessels constrict and don't leak as much.
Calamine lotion helps reduce the itch and absorbs the oils.
Oral antihistamines help. Cortisone creams usually aren't strong enough in the beginning but will help block the itch about two weeks into the rash. Even oatmeal helps absorb the oozing. As you might have guessed, there are a multitude of folk cures. There are people who are allergic to almost anything.