I just thought of something else. First, how old is your daughter? Do you know if she hears a "clicking" sounds when she opens or shuts her jaw? Does it hurt under the ear? Does she grind her teeth at night or clench her teeth throughout the day? The reason I am asking is this swelling could be caused by TMJ, this is Temporal Mandibular Joint, and when it is not aligned right, a person can have all kinds of pain and trouble. For this, you would need to see an Orthodontist.
Try applying ice to the jaw area, leave on for about 20 minutes then remove, do this about 4 times a day. As to the giant bump, I would see a dentist about that.