Hello, I have a nickel sized (movable) lump behind my right ear near my hair line. I ve had it for about a week, it feels movable and feels like a rubbery bubble, almost like theres fluid in it, but its not red. Should I be concerned that this could be something serious? I ve asked my parents what they thought, and they have many times said not to worry about it, but it has been driving me insane for the last week. I don t think its anything serious, like cancer, but I just want to have an expert s opinion on this. I m 17 years old male and again, I feel like I m developing a OCD obsession over this.