Ay, diaper rash talaga yan, mama! Pwede ang petroleum jelly pero honestly, a few of us moms swear na mas effective ang diaper cream specifically made for babies like Mama's Choice or other trusted brands kasi formulated sila para sa sensitive skin ng newborns, petroleum jelly lang works pero sometimes need something stronger. Make sure din na linisin mo mabuti ang area bago mag-diaper, change frequently, at let the skin breathe kung pwede mo, pero if it gets worse or sobrang red na, better check with pedia kasi minsan may fungal infection na involved na need ng prescription cream. Kapit lang, normal yan sa newborns especially sa tag-ulan, alam mo na yan hehe!