Sabra-help diaper rash for a week

Sabra:
I hope you can help me.
When my son was close to two years he developed a diaper rash that lasted for almost a week. I put desitin, and other ointments to heal, but the redness disapeared and in place there were pale white patches that increased and spread from his buttons to the left side of his leg trunk. It didn't spread as white, but as a terrible rash and then after a week or so he appeared with the pale patches that spread and became whiter. His pediatrician gave him cortison with fungus cream, for long time. Since she said that it was versicolor. I'm afraid that the use of these treament will cause damage to my son who is now 5 years old.
I read some of your replies on these forum and like very much your interest in helping people.
would you help me? He wants to be cure and want me to put the creams prescribed by the doctor.
I was wondering if there is another way to heal his skin.
God bless you
and
thank you for helping others.