I had a simular problem, I had woke one morning with my eye very tender and sore, and like your daughter, it hurt to close it and blink. It had also swelled up a bit. The tenderness only lasted a few days, it gradually became less tender. But after all that had passed, I felt a little bump under my upper eyelid. It seemed to have gotten bigger within a few days after noticing it. But, the tenderness and pain didnt return. I went to the doctor, and they told me I had a "chaslion cyst" which I think they mentioned it also being another form of "stye." Whicb is cause by natural oils produced in your eyes clogging, which is also how a chaslion cyst is caused. Have her gently apply pressure and feel around under her eyelids top and bottom.
Hello and hope you are doing well.
The eye pain could be due to stye, this is caused due to blockage of secretory glands situated in the eyelid. This can lead to infection of the gland, causing symptoms of pain, redness and swelling. The other causes could be due to injury, xanthelasma (yellow patches), papillomas or cysts. She will need to consult your primary care physician for further evaluation.
Hope this helped and do keep us posted.