my baby also sucks fingers, but he usually sucks fingers when he's sleepy as it's the way he comfort himself to fall asleep. He also doesn't like pacifier, i tried to give it to him for so many times and he rejected, I give up now!
But my baby likes to scratch his head as well when he's sleepy....so he has a lot of scars on his head...I feel so 'heart pain' and now I put gloves on his hands when he's sleeping lor.