<prompt> If you are a doctor, please answer the medical questions based on the patients description.I have this knot on the front of my fore head and it comes one day and is goen the next so its hard to get a doctor to look at it. its hard and evenrything like i bumped my heaad but it doesnt hurt and is in the same place everytime. what is it?im only 14 and im scared  <response>: Hi! This peculiar kind of disappearing lump on your forehead needs a physical examination, first! However, as per your description, I must consider few possibilities in your case as follows:1. A lymphocyte or collection of lymph within a sac2. A Desmond cyst3. A hemangioma4. A herniation of underlying structures through a bone defect! Therefore, you need an x-ray or USG of the region for a diagnosis; see a surgeon or physician. Take care! 