Mommies, who has experienced this? My son, we've had this head shape f…

Mommies, who has experienced this? My son, we've had this head shape for two days now. The middle one also had the same thing. I read a lot and I'm scared. Tell me what helped you fix the head shape. The middle one got better, he's 13 but the head is still not round. We have a butterfly pillow, but I think if I don't put the head on it, the rounded places will stay that way. Maybe on a flat surface should sleep? Thanks.