Cut inside?

So I have this thing on the inside of my lips on my vagina. It looks like a cut and it's been there for a while. It's about 2mm big and only noticeable if you pull my lips open fully (cause they're not small tbh) 
It genuinely looks like a circular cut and I put cream on it and it doesn't go away? Any idea what it could be? Surely if it was a cut it would have healed?