I've been using this as a spot treatment for any acne that I have and it works wonders.  I use it at night, and the next morning any spots I have will be greatly reduced in size and almost completely healed.  It does have a very pungent smell, but I got used to it quickly especially when I only use it as a spot treatment.  Since only a small amount needs to be used (I use less than one pump on a clean cotton swab) it's going to last a really long time.  I've been using it for about four months now regularly and I still have more than half the bottle left.  This is an amazing product, especially if you suffer from cysts or painful acne.