Hun, get out to a chemist and get "Nappy Mate" - its the stuff that they use at Princess Margs. Its really thick paste and you put it on super thick too, to cover the rash entirely. Its about $9 from the chemist but it is the absolute best stuff out there.

Bepanthan can be used, but it's not really thick enough to give the rash good waterproofing. Have you got any zinc cream like Sudocream hanging about? I would use that is you do.

HTH - fingers crossed your little one heals quickly!!