My 11-month-old boy has been having a bad bout of nappy rash. the one time this happened before it cleared up with very frequent changes and lots of Drapolene. This time, despite trying lots of changse (including 3 or 4 at night, ughh) nappy free time, drapolene (and other creams), he doesn't seem to be shaking it. Any thoughts before I take him to the GP???