What Causes Lumps On Vaginal Lips?

I found a strage lump about the size of a pearl on a vaginal lip a while ago. i managed to squeeze it out, it didn't hurt and never did but it was still pretty wierd. when it did come out i found it was a round, black, oval and opaque surface-thing that didn't even look like it was originally made by a human body, more like and alien egg. I cut open the thing to see if i could find a fetus but this chunky brown substance was all that was present. I've been probing the internet for months now trying to figure out what it was and avoiding having to speak to anybody about it out of embarrassment. this is kinda my second to last resort. can you define what i might of found?