your head grows, obviously, until some point. Bones can still change when you are grown up, but the head is more fixed. That means less growth through external influences (physical impact, hormones...) but there's also less bone loss when you are old. The overall size and shape stays more or less the same, but what definitely changes (until you die) is the size of the nose, for example.
---------- Post added 2010-08-30 at 12:01 ----------
Many people's bones aren't even fully hardened until their 30s.
Skull = static
other head bones (nose, jaw) = not so much