TL;DR: I went to the doctor yesterday (8/29/16) and she said it is either a blocked sweat gland or lubrication gland. Her advice was for me to keep taking baths and it will continue to heal on it's own. If it gets worse, then I need to go back. I took epsom salt sitz baths. Epsom salts help with constipation, but if you aren't constipated, it could cause diarrhea or the urge to go. You should check with your doctor before using it or just take regular baths without it.
I had the exact same problem that most everyone else has mentioned: Hard bump in my labia. It was irritated at first, but didn't hurt. It got bigger the next day and started to hurt and was itchy. That's what prompted me to find an answer online. I'm so glad I found this site!
I took several sitz baths (a bath in which only the butt and hips are immersed in water) with epsom salts. After the first 2 baths, I didn't really notice any change in the size, but the pain and irritation lessened. After two more baths on the 2nd day, I noticed it was starting to get smaller. By the next morning, it had a white head and I didn't even have to touch it for it to "pop". I know, gross, but whatchu gonna do. Some white pus and blood came out. I made sure to clean it with saline (I happened to have a fresh nasal saline spray around). I patted dry and I only wore skirts or loose shorts for the next few days.
I noticed it on Thursday, it seemed a little worse on Friday so I made a appointment with my doctor for the following Monday. The problem resolved itself on Saturday morning. I kept my doc appointment just in case it could be something else. Now it's gone. Yay!
I'm not a doctor, but I would recommend going to see your doc if you are taking baths and not noticing any change in size or pain or if you have a fever.
I have been dealing with this for over 30 years. Mine are on the left labia hard bumps deep within the skin. They appear within 4 days of starting my period and are gone 3 or 4 days after. Extreamly painful. So 10 years ago I went to my doctor she removed the bump to send to the lab. When I went back she told me that it was herpes and gave me some medication and a script for lidocaine to mix with yeast infection medication (helps so much for the pain) and sent me on my way. I took these meds for almost 2 years they never stopped the bumps (I have 3) and the one she removed came back in the same spot. My poor husband (married for 26 yrs) I made him get tested for STD's 4 times all test negative. So I know you can't have unprotected sex 2 or 3 times a week with someone with an STD without catching it. So in my mind it is not Herpes. I can not wait for menopause in hopes that they with finally stop. If anyone has any answers I am so ready to hear them. The bumps came up yesterday and I am out of lidocaine lots of pain today.