Aw, poor baby! Rashes are so common at that age, pero depende talaga sa type, heat rash, diaper rash, or food-related, iba-iba ang gamot kaya best to check with your pediatrician muna para sure kung ano exactly yung problema bago mag-apply ng anything. In the meantime, keep the area clean and dry, at avoid irritants like strong soaps, pero talagang kailangan ng doctor's opinion para malaman kung anong ointment ang safe at effective para sa baby mo.