I have used it for many months. It is not a miracle cure, if thats what you are looking for but it definitely helps to control acne. It is very antibacterial. I drink it also...2 tbsp in a glass of water. I use it to mix Bentonite clay for a face mask and often apply it after the mask. I let it dry and then put tea tree oil on pimples followed by my moisturizer which is normally aloe vera gel at night and emu oil in the morning.
If you decide to use it you should buy only Organic apple cider vinegar. The non-organic ones have chemicals which will be absorbed into your body and could make your problems worse. That is very important. Also make sure you test it before you use it. Put a little under your chin and leave it for 15 minutes or so. If you have no reaction then you are not allergic. I put it directly, full strength on my face but some people can't handle it. I would try mixing it with water, starting with a low amount of vinegar and then increasing the ratio. Maybe start with a 5:1 ratio and move it up till you are full strength, if your skin doesn't get irritated. Good luck!