Circumcision

Hi, I had my son 6 days ago and before we got discharged from the hospital I made the decision to get him circumcised. They told me to keep his penis wrapped in gauze and aquphor until the ring falls off on its own. And today it fell off. Now I have 2 questions

1. How do I keep the foreskin from growing back? ( I’ve been told it can grow back )

2. How do I care for his penis now that the ring is no longer there?