A lump on the right back of the neck may be a sebaceous cyst or a lipoma. Sebaceous cysts are formed when the sebaceous gland opening is blocked, usually with a black spot or a black head on the surface that is the opening of the sebaceous gland, with a tofu-like substance inside and a cystic wall completely wrapped outside. Therefore, after the diagnosis of sebaceous cyst is clear, surgery should be recommended to remove it. Lipomas can also form subcutaneous masses, which are generally softer in texture, have clear borders, are very mobile, and are not painful when pressed. Small lipomas can be followed up as they are benign lesions, or surgically removed if they are large and affect the appearance or are painful.