How do I care for my new and swollen snug piercing?

This is my first piercing and it is a tad swollen, there's barely any room within the piece and I'm getting a little freaked out. Also, the piercer advised to move it "in and out while I clean it," however, every single website about piercings that I've found advises otherwise and states that you shouldn't change the piece until at least 12 months, while my piercer said 4 weeks!

How do I address the swelling? and until when is swelling considered normal? I've heard of people's snugs swelling up after 4 weeks! I'm afraid he might have put a bar that is too short or that I'm having some sort of reaction to the steel.

Thanks!