Help about my Lip Piercing, just General Questions?

Well, i got my Lip Pierced Today, im a 14 year old Guy, and, it kinda hurt, a little, But, Yeah, the Dude put in a horseshoe thats really big, So, 1)How long do i have to wait to change it to a smaller, tighter one. And, the guy told me to buy Blue Wave, And , ive used taht a few times, But im really scared, i REALLY want it to heal fast, and not get infected, so 2)What should i do to get it to Heal Fast, and not get infected. Also, it Kinda Hurts. like, every soo often, like once an hour, it hurts a little, 3) Why? D:, Thanks ahead of time