If it's really bad with blistering, I used 3 days of Hydrocortizone creme 1X per day, and Nystatin (Rx) 4X per day. (per the pedi)
Otherwise, I wipe front and back (even if just wet), then DRY, then apply Desitin or other creme. It's important to dry the area before applying the cream because if you don't, the cream actually keeps the moisture in, rather than locking it out.
When Ellie has open sores due to diaper rash we switch from Desitin to Aquafor or vaseline. It doesn't sting like Desitin can.
Lots of naked time or cloth diaper time with a loose prefold to get some air.
I've used the Aveeno bath soak but it says not to drink and Ellie chews and tries to drink from her bath cups so we don't use that anymore.