What causes localized swelling on on side of the cheek, with mild pain, and headache on same side?

Okay, so here's my dilemma. Today when I came home from work, I noticed on the right side of my 6 year old daughter's upper cheek was light red. I also noticed that a localized spot on her upper cheek was swollen a bit, my mother ( who watches her while I go to work) told me that it wasn't there before I came home from work. So anyway, my daughter said it hurt a bit, and I examined her cheek to see if maybe it was a bug bite of some sort, but it was not, there are no tiny puncture wounds. So I had her put ice on it, and I also put some cortisone on it as well. So then about a hour or so later she came to me and told me she had a headache on the right side of her head and it was in one area. Now mind you, my daughter never comes to me and complains of her head hurting at all. So my question is, what might this possibly be? And should I be concerned? My daughter is not allergic to anything that I know of. And she claims that she wasn't doing anything out of the ordinary today.