Bellybutton gauging?

So I don’t really need to be told that it was stupid because I know it was, I was just in a hurry and didn’t actually know there was a difference..but here’s my situation.

I didn’t actually know belly button rings had different gauges. Ever. It had never really been something I paid attention too. Everywhere I’d bought one from previously was either the same size, or I definitely wasn’t paying attention. But I went to Spencer’s to get a nose ring (which I know the gauges of) and they were having a buy one get one free sale so I quickly picked out a belly button ring. When I got home I noticed it was a 12g. I figured to just go for it because

• it was cute, and free

• I’ve had the piercing for 6 years so it’s definitely healed enough anyway.

• it might be the size I’ve had the whole time.

It wasn’t very easy to get in there, I figured it was because I’d been without one for a few weeks, but it’s never been that difficult before. Now it’s very itchy and irritated. The redness has went down a lot but it still kind of hurts. So what I’m wondering is, is it just bad metal? Is it causing a reaction? Or was it too big? And if it is too big is there any specific care I should do to it. I’ve been spraying H2Ocean on it because it makes it feel a little better.

Please don’t tell me that was dumb. I know it was careless but it happened. I just need some advice on what to do next.