As for the pimples that are generated in the hair follicles. The overproduction of sebum resulting from the hormonal changes that Scott is experiencing is the initial event responsible for his acne. P. acnes is able to utilize the glycerol in sebum for fuel; in the process of doing so, it produces free fatty acids. These fatty acids lead to the production of inflammatory cytokines, which lead to vasodilation and increased vessel permeability. These changes allow for immune cells to move into the follicle. As the immune cells work to eliminate P. acnes, dead cells, bacterial waste, and pressure (from the massive influx of cells) will build. This ultimately distends the follicle. If great enough, this buildup will be visible on the skin as a pus-containing papule.
