nope, your baby has just found a way of sleeping thats comforting to him. We used the baby sleeping bags (grobag) up until about a year old. You can get them in different togs for summer and winter sleeping. he won't have a blanket to put over his face then. If they aren't for him, get one of those thin blankets with the holes in? I know you're worrying incase he suffocates, but he'll be moving around all night, he has the strength to move his head and body. its not like a newborn who pretty much stays where you put it all night. Could you tuck in the blanket tighter around the bottom of the cot so he can't pull it up?