My boy does this, too. We've had him since March, and he's still what I would consider tiny. Was supposed to be a well started baby, but I suspect we got a hatchling. His sister was bigger when we adopted her. She was used to people as well, where he was barely before leaving for his forever home. We hand feed, pet him, and talk soft to him. Little by little he's trusting us more. He still does his open mouth and beard before out time, but once out he relaxes a bit. He can still be flighty and jumpy but he's just a baby. Your baby will come around. Just listen to the awesome people on here and you and your baby will be fine.