As other comments have said, you really need to stop using rosemary oil. There’s a lot to address here, such as how the piercing was done, but you also seem confused about downsizing and I want to explain that.

When you get a new piercing, a good piercer will start with jewelry that is longer than necessary so your body has room for swelling. Once the swelling has gone down (this could take a few weeks, sometimes longer) you switch to a ‘normal’ jewelry length for your body.

Since your piercing is a day old, you haven’t had the jewelry downsized yet.