Is this a fungus?

Lauren

So I have been researching and all I have found is that it’s a nail fungus. I noticed this yesterday. Has anyone else experienced this with your little one and what did you do about it? She has a wellness check up tomorrow so I’m using that as an opportunity to talk about her toe. I read raw apple cider vinegar helps and have been applying that and soaking her feet in the vinegar bath. Anything else I can do to make it go away?? Thanks.