Easy Bruising

I posted last week about my son headbutting things out of frustration to the point of bruising. Well he's stopped doing it, thankfully, but he's still got these nasty bruises and not only are they not going away, they seem to be getting worse. 😭 His forehead is littered in brown and red marks of various sizes. They're not blue or green or black thankfully but I'm still worried. I tried looking it up to see what could be causing it since I don't see him hitting his head anymore, but I couldn't really find anything other than he just possibly bruises easily. If it was elsewhere I wouldn't be so worried it's just it's his head... He has a ped appt on the 3rd of Jan so I'm trying to hold out until then. My husband thinks he could be hitting his head on his crib in his sleep and he does tend to sleep near the sides not in the middle.