It's extremely frustrating to do absolutely everything you can to prevent diaper rash, only to have it keep showing up or sticking around. If you're winning every battle but losing the War On Diaper Rash, you might consider making some random but strategic changes.
Since there's not one cause of diaper rash, and no single cure-all, you might find an elusive solution to your particular quandary by performing a methodical switch-out. For instance, some disposable diapers have chemicals in them that don't react well with some children's skin. So, changing to a different brand of diaper may turn the tide. If that doesn't work, consider switching to cloth diapers.
Likewise, if you use cloth diapers, consider switching detergents or switching entirely to disposable diapers. There are a variety of different types of wet wipes, and some have perfumes or other chemicals that may be irritating your baby's skin. Try switching to a hypoallergenic, unscented wet wipe.
Certain foods ingested by breastfeeding mothers (such as anything tomato-based) can also aggravate diaper rash. Since your infant is receiving his or her nutrition from you, make sure to speak with your pediatrician before making any dietary changes.
You may also consider switching to different kinds of baby lotions or powders, in case the type you currently use are contributing factors.
And as you'll learn in the next section, if you're not using a "blocking agent" (read: butt cream), you very well may want to start.