Our DS had a lump like that on the left side of his head. We noticed it early because he had no hair. It felt just like his skull but was a different shape to the other side of his head. We took him to the Dr. and the doctor said that it was just his head shape. He said that maybe it was from how DS slept as a baby as he did favour that side when sleeping. Most importantly he told us that it was nothing to worry about as it wasn't a lump, it was his actual skull.

Hope everything is O.K. with your DD.