Health question, what is this?

[Bennie1986]

Since it is one continual line it suggests a scape that is healing or maybe a current minor scrape. It's hard to be certain from the photo.

Did this just show up, or has it been there?

If new, you need to inspect your cage for things and areas that may cause injury.

Sorry if i wasnt clear, she has had this since we git her 10 months ago.