Bear in mind, Pro Activ is a celebrity endorsed product, and a Benzyl Peroxide product. These two factors make the product expensive and unhealthy for your skin. The product is also sold on a automatic contract, i tend to stay away from a product such as Pro Activ.
I understand there is a generic version of Pro Activ that is not under the same marketing as Pro Activ, and the results are similar if not better than results seen for the original Pro Activ product.
You have described an acne condition very similar to my condition. The best treatment i have found is Acnexus, which is a natural exfoliating product with very good results that can reduce acne in a very short amount of time of around 3 days.
Many of the acne treatments you have tryed are external treatments. I have found internal treatments more effective. Drinking water helps the complexion as does skin support vitamins, in particular a Zinc suppliment, probably something your not likely to hear from a Derm. Although internal treatments tend to take a longer time to take effect, a corabination of internal and external treatments is highly reccomended.