Hi, I noticed a puss filled legion on my vaginal opening. I am hoping that it is a vaginal boil caused by an infected ingrown hair but I am so scared that it is an STD. I feel no pain nor itchiness at all. As I was examining myself, I also saw that there were some whitish coloration/patches around my inner labia. Again, I have experienced no pain/discomfort/itchiness. I got tested for chlamydia, syphilis, and HIV earlier this year, and have not been sexually active since then. I am planning to talk to my doctor about this, but It's going to be a while until the appointment and I am so worried it might be STDs, bacterial infections, or some type of cancer. I can't get this off of my mind and I am terrified. Please help WARNING: GRAPHIC IMAGES
how long have you had this?
Dear lemon,
I don’t think it’s a “pus-filled boil”. This would be very painful, red and inflamed and you say that the big yellow lump is painless. It’s much more in keeping with a sebaceous cyst (a blocked oil gland). And I don’t think it’s an STD because you were checked quite recently and not been sexually active since. Maybe you can share the photo with your doctor and ask them to comment on whether they think it’s a sebaceous cyst.
Adhari
Hello, I just noticed it around 5 days ago.
I wanted to also say that I don’t know how long I’ve actually had it, I probably would not noticed at all if I hadn’t decided to check down there.
Thank you for the input, yes I will do that. I am really hoping it is that, but I am worried bc cysts do not usually contain pus (or at least I think?). And the shape is odd, I would think that any growth would be round/circular and not the rod shape that I have. Oh well, I will just have to wait and see. The anxiety is the thing killing me, this may be tmi but I stayed up all night worrying and researching what it might be, and eventually was convinced it was some kinda freak bug larvae growing inside of me. It took my partner hours to calm me down to a rational state… 
IT doesnt look like any sti to me might be a boil of some sort. I know what you mean about being up all night researching and thats the worst thing we could do is self diagnose only leads to more anxiety.