My little one is 3 months old and I've just started to take off his mittens to let him adventure with his hands but he keeps sucking his fist once mittens are off. His fingers have become red because of sucking. Is it okay for him to keep sucking his hands? How do I prevent him from constant sucking? Hope to get some advice

Wow... it is actually recommended that mittens be worn till 6 weeks of age, so it is kind of late to be off mittens only now. It is natural for babies to suck their fingers. Just let him be. Mine does it because I don't want to introduce a pacifier to her. Non-nutritive sucking is very important to babies as well as this makes them feel comforted. http://sg.theasianparent.com/are-pacifiers-really-good-for-your-baby/