like Sassy said, dont stress too much and dont let the MCHN give you the heebie jeebies. My DS was a rather large bub and had a big head refussed tummy time and as a result developed a really bad flat spot on the back of his head - his head was literally flat at the back which was caused from the weight of his head and constantly lying on it (as babies do). After a consult with our pead it came down to basically things would sort themselves out and to encourage tummy time and once he was big enough to try to keep him upright (like sitting up in the pram, highchair etc). He is now nearly 8 and has a perfect round head the flat spot pretty much corrected itself by the time he was twelve months old.