I'm a 38 year old white female in very good health and normal weight. I've had a few unusual moles removed, all benign. Yesterday I noticed a small(about 6mm)lump under the skin on the underside of my forearm, about 4 inches below my elbow. The lump doesn't hurt or itch and it is not hard. It seems to be smooth and oval shaped and I can't see it on the surface of the skin when I look at it. The lump does not seem to be movable. Interestingly, when I raise my arm above my head, the lump becomes much less obvious to the touch, and when my arm is hanging at my side the lump seems to come back - almost as if the lump is related to vascular pressure. Also, if I rub the lump, I can almost massage it away, but then it comes right back within 30 seconds. There is no vein visible through the skin near the lump. There are two tiny (about 1mm each) slightly red marks (not raised at all) on the surface of the skin directly above the lump. Maybe unrelated. The thought of a spider bite crossed my mind, but with no itching or pain I think it is unlikly. Does this lump sound like anything worrisome to you? Is it worth making a doctor's appointment? Thank you very much for your time and consideration.