I've seen a lot of posts about preventing stains or how protected vs. unprotected deal with spills.

Just found a stain on my ottoman. Not sure how long it's been there, or what caused it but it has a distinct circular shape that could have only come from someone putting a plate on it. the stain is darker colored than what's around it. I'm wondering, ive seen mentioned that oils can "absorb" and dissipate over time. is this true for all stains and all leather types? Maybe I should just give the stain a name because it will now be a part of it, or will it slowly go away over time?
Is there any way to remove it without making it worse?