Eh, ruam susu kan memang common kat newborns, biasanya hilang sendiri dalam few weeks je, a few of my mum friends just kept the area clean and dry, pakai cotton cloth yang lembut je. But since it's worrying you, better check dengan pediatrician first to make sure it's just milk rash dan bukan something else, especially before trying any new products on baby's delicate skin, ye?