Is Clobetasone Recommended To Treat Rashes In An Infant?

hi, i have a 6 month old son. he has rashes on his butt. i consulted a dermatologist, he says, it could be due to change of weather, its summer here...he asked me applt clobetasone ointment. I did not see any improvement even after 3days rather it went worse, i went to his pediatretion. he says its funal infectgion and has given me another ointment, sebidin plus. i still dont see any improvent. It was a rash in a very small area initially. Now it has almost covered his left butt and now a small area on his right too. i was using nickers(pampers) during night only. Please advice.