My Grandchild, 12 Months Old, Fell Down The Carpeted Stairs

My grandchild, 12 months old, fell down the carpeted stairs Saturday morning (3 days ago), hitting her forehead on the hardwood floor at the bottom. My daughter took her to the ER, and CT scan and X-rays were negative. There is a large bruise on the right side of her forehead (not temple), and a smaller bruise on the left side (not temple). She has shown no symptoms whatsoever, and is eating, sleeping, playing, and behaving normally. This evening my daughter was bathing Molly, and noticed that her soft spot is bulging, and feels like a large lump. Molly still is laughing, playing, eating, etc normally. No irritability at all, pupils of eyes fine, no lethargy, no indication of pain. I think they should take Molly to the doctor to check this out. Can you give me your advice, please?