Alamak, biasa je tu! Babies semua akan ada air liur yang berkumpul macam tu, especially when they're teething or just exploring their mouth, some of my mum friends kata their babies pun sama, very normal phase. Tapi kalau dia ada kesulitan menelan, kepala selalu miring, or air liur dia banyak sangat sampai rash kat chin, better check with your pediatrician just to be sure semuanya okay lang.