For a 4-month-old infant in Singapore, the typical dosage of paracetamol (also known as acetaminophen) is usually around 10-15 mg per kilogram of body weight, given every 4-6 hours as needed, but not exceeding 5 doses in 24 hours. Make sure to use a liquid formulation designed for infants, and consult your pediatrician for the exact dosage based on your baby's weight and health condition. Always check the product label for specific dosing guidelines and consult a healthcare professional if you have any concerns.