I use apple cider vinegar full strength. Wipe my face with a cotton swap soaked in ACV three times a day and I also drink it three times a day. It keeps my adult acne away. If I stop using ACV the acne comes back.
Apple Cider Vinegar
I had a skin issue on my face called rosacea, it was extremely red all of the time and I had blackheads and even brown spots. I used ACV or distilled white vinegar. First few days of use, (especially the first) my skin was got red, sensitive, and was stinging. My face got dry and began to flake a week later. From my experience, it is because I was making new skin for my face and the ACV was taking off the old stuff. It will hurt or sting maybe dry for mainly the first week or if you have a infected area in your face that it is cleaning (working).
I kept doing this since November of 2014 and it all completely left my face at my surprise. I also used it on my arms and my freckles are almost gone and my hair on my arms are back to translucent. I slept with this stuff drying on my face, but did not go out in the sun with it on. I would usually either wash it off after 30 minutes or sleep with it at night. ACV helped instantly with tummy aches and drove my blood sugar down. It does have a burning sensation when you take it straight. I think it is because of the repair work it could be doing, I also believe it is a declogger for arteries.