It's very sticky, so it's best diluted til it doesn't feel sticky on your skin. Also, if you live in a humid area, it will pull moisture out of the air and into your skin, which is good, but if you live in an arid area, it will pull moisture out of your skin and into the air, so that is something to think about. No idea how it works on acne though.
Vegetable Glycerin is used as a moisturizer. It will not prevent acne, but it is used on dry skin by a lot of people. The warning labels says not safe for skin contact, but this is in concentrated form. Below is a formula on how you can mix it with water and oils for at the following site.