I've previously commented on Mario Badescu's pink spot serum (reviewed here) but have since converted to another version: Mizon's A.C. Care Solution Acence Blemish Out Pink Spot (why do so many Korean products have ginormously long names?!), an acne treatment I've liked enough to re-purchase once already. =)
The gist of pink spot products is that the user dips a Q-tip past the yellow liquid, into the pink sediment, draws it out and then dabs it over the blemishes for overnight therapy. Sulfur, an active ingredient of these pink spot products, has a rap for being potentially irritating and stinky. The stinky part is right but I've found my skin responds well to sulfur if it's in a good formulation and I use in moderation. Many traditional acne treatments like benzoyl peroxide don't seem to do much for my breakouts so I'm glad I have a fall-back product when I'm not trying out new acne ingredients.