My 2-year-old child has a small lump on the abdomen. It is smaller than a black pepper seed. I noticed a small black mark on the skin that looks like a wound, and when I touched it, I could feel the lump underneath. Two doctors said it is a lipoma, while another doctor said it might be a sebaceous cyst caused by infection. He don't have any pain .. active ans eating very well.     I asked about doing an ultrasound, but the doctors said it is not necessary. I want to know what it really is and whether it will disappear on its own or need to be removed. I have attached the image of my boy with penmark on stomach