Hi and welcome to YT - CONGRATS on your new baby
!
No, he won't likely get too much bigger - so be careful of his size as he's still probably learning his limitations at this age. You might want to put a bell on his collar for awhile - until you're used to having him underfoot.
As far as the fur on his head - it can often look thinner than it is in puppies bc lighter hair is coming in under the darker hair, which can give the appearance of thinning.