Are you sure that you are using a completely herbal based testosterone booster and nothing that contains anything hormonal like pro-hormones?
It sounds to me like you are using pro-hormones. Acne is a very common side effect from pro-hormones.
Whatever you are taking, if it's causing side effects, you should stop using it. I really like the natural testosterone booster HCGenerate from n2bm.com. I would try using that instead. HCGenerate is a completely herbal based testosterone booster with no banned or illegal ingredients. I have never once heard of anyone experiencing acne from using HCGenerate.