Bump on my vagina..

So I started to feel a little itchy down there, like it felt like I had a start of a yeast infection, and I know, scratching makes it worse, but it was awful, so I kinda itched myself a little, then I noticed I have a small bump on one of my lips.. It's like a smaallll pea size bump, this has showed up before but gone away. What could this possibly be?! Should I be worried?! Oh god, it better not be a std, I'm married and have only been with my husband and he hasn't been with anyone else either. Last doctors appointment I had they said I had zero std, could one just show up like that and go away?! Omg.... HELP?! I'm freaking out and overthinking it now!!