Ay, anak ko din nag-experience nito last year, nakakaalala ako! Could be heat rash or an allergic reaction sa bagong sabon, kahit gentle ang label, sometimes ang baby skin talaga just doesn't agree. Mag-try ng mainit lang na tubig without soap muna for a few days, or use a very gentle brand, pero honestly pati yung few of my mum friends na nag-encounter ng ganyan, nag-consult agad sa pediatrician kasi hindi kayo sure kung ano exactly ang cause. Better safe than sorry with baby skin lalo na if it's spreading or hindi nakakaalis!