The quiet, calming dreams suggest that Matty shouldn't actually be afraid of his power. Even if healing the frog in a way that startled him was scary and unexpected, the dreams indicate that on some level, Matty likely understands that this power is a good thing and will allow him to serve his community going forward. His fear also explains why he's trying so hard to keep it secret: presumably, he wants to be able to understand it before he shares it with others. In this case, Matty seems to feel the need to educate himself.