The oil from the oil gland is important in two major ways. The first is that it waterproofs our skin. The second is that it flushes out bacteria lurking inside the hair follicle. The importance of this action is obvious during puberty or when eating a high fat diet. During puberty many youngsters get pimples. Pimples are infections of the hair follicle. The oil (sebum) is too thick during puberty or during the ingestion of fatty foods to effectively flush out bacteria. The thick oil blocks the opening to the the hair follicle and creates a haven for bacteria. Bacteria therefore thrive and multiply in the moist, warm environment of the hair follicle and initiate an immune response.