Sebaceous hyperplasia is an enlargement of the skin oil glands (sebaceous glands) causing benign small bumps. These harmless bumps often appear soft, yellowish with a cauliflower-like or doughnut-shaped appearance ranging in size from 2 to 3mm. They usually appear on the forehead and cheeks, where oil glands are plentiful. While it is not a painful condition, lumps may be irritated by shaving, glasses or clothing.