I would give him another weeks, but that doesn't mean he will stop hissing at you. A lot of mine still hiss at me. I've had one since April who still hiss at me every time I open her tub. It's kind of cute.

Babies are more prone to biting too because they have evolved to have an I am food and everything bigger than me wants to eat me mind set. Give him time, he'll settle down eventually. Don't freak out if he snaps at you either, he's just following his instincts and trying to "survive".