There are many reasons for the formation of acne on the forehead. First, if you stay up late for a long time, live irregularly, and overeat, your liver will not be able to discharge toxins normally. When toxins accumulate, it is easy to cause acne on the forehead. Secondly, if work and mental pressure make people depressed and lead to endocrine instability, it is also easy to have acne on the forehead. Finally, if the pores are blocked due to long-term exposure to sunlight or ultraviolet rays, greasy skin and poor cleaning, it will also cause acne on the forehead, so you should eat a light diet and pay attention to rest and sunscreen.