A lump on forehead for no reason may be caused by epidermal cyst, boil, dermatofibroma and so on, which can be treated with medication and surgery according to the cause. 1. Epidermoid cyst: It is a kind of cyst containing keratin in the dermis, which is a round elevated nodule, skin-colored, elastic, movable, with no self-conscious symptom, and can occur in any part of the body, and can be cured by surgical excision. 2. Boil: It is an acute purulent inflammation of the deep part of the hair follicle and the surrounding tissues, often induced by Staphylococcus aureus. The lesions start as follicular inflammatory papules, and then the inflammation extends to the surrounding area, forming hard nodules with redness, swelling and heat pain. It can be treated with topical 3% iodine tincture and mupirocin ointment. Cefixime and other antibiotics can also be taken orally if necessary. 3. Dermatofibroma: This disease may be a reactive proliferation of fibroblasts triggered by small skin injuries, rather than a true tumor. Typical skin lesions are slow-growing round or ovoid solid nodules with smooth or rough surfaces, often single, and the lesions are often persistent, and a few of them may subside on their own, which can be treated by surgical excision. If you have a lump on your forehead for no reason, you need to actively consult a doctor and follow the doctor’s instructions for reasonable and standardized treatment.