My 3 year old son suddenly developed a good sized lump on his forehead near the temple/ scalp line. A little bigger than a quarter in size, red and soft but not moveable. He didn t bump his head. I was with him all day. It was nickel sized at lunch and twice as big by dinner. It just came up out of nowhere. He says it doesn t hurt even when we touch and press on it. Tried cold pack in case of bump and Advil as anti inflammatory but no change. What is this?? Freaked out.