C.O.
this is the problem with modern technology - we aren't doctors and we research things and self-diagnose things.
He's crawling, he's moving - expect bumps and bruises to happen. He is expending more energy now that he's moving so he will sleep more!!
Okay - so his head is small. If the MRI came back fine - then he's just smaller than the "average" child. That happens. In 6 months - he may be ahead.. you never know...
CALM DOWN!! DO NOT PANIC!!! I'll tell you a funny story - my son was all of 4 months old and one day after him trying to sit up and do things - i noticed, what I would call a bruise - now keep in mind my 1st son was 6 weeks preemie and now almost 20 lbs (can you say butter call turkey?) I had to lug him around and I thought I might have squeezed too hard - called my pediatrician crying because I thought I had hurt my son - they made an appointment for me within the hour - I went in and took off my sons outfit -the dr - smiled graciously and told me - it's not a bruise - it's a birth mark - a cafe au lait - my son as a "stain" on the back of his leg...the Dr was wonderful and told me DO NOT PANIC....I knew this but was soooo scared since it had been 14 years since I had had a baby!!!
STOP PANICKING!! STOP RESEARCHING THINGS!!! You are making yourself nuts and will not be able to enjoy your son because you are too busy researching things he MIGHT have.
He is GROWING!! They grow the most in their first year of life than they do any other time. At the point now - where he's getting more active - like I said - HE WILL SLEEP MORE. he will get bumps and bruises.
He should be going into the Dr for his 9 month well child in a few weeks, right? IF the bruises do NOT go away BEFORE then - then call. But I bet they'll be gone in a few days if not sooner. STOP PANICKING!! TAKE A DEEP BREATH!!! STOP RESEARCHING!!! You are going to give yourself an ulcer or a heart attack if you keep trying to find something wrong with your son.