If you keep on seeing changes go to an obstetrician. Or your primary doctor. Although if you want to really know take a home pregnancy test. Either way go to a professional.
So, I have been reading up on this forum trying to "self diagnose" myself because I have a small blister like thing on my outer vaginal lip, I figured it must be an ingrown hair since I just shaved 2 days ago and its itchy and I have had one down there before. I wanted to maybe give some insight to anyone, a few years ago when I was 22, I was having sex, wasn't really in the mood and the next day I woke up in pain with a blister. Of course the first thing I thought was STD!!!! So I rushed to the hospital (since it was faster than making an actual doc appt.) The have gyns available there so they called one in and she said friction can cause blisters. She also said swollen sweat glands, bacteria in an ingrown hair can make blisters swell. If it is just a blister, things like a warm compress or a warm bath will help with the pain, and also, if you can bare it, I like to wrap ice in a wash cloth and rotate hot and cold. Good luck to all and I hope everyone found out what the problem was.