I think you guys are scaring LU too much. Sounds to me like she stubbed her toe, and it is purple because of bleeding under the skin (you know, a black-and-blue mark, just this time it is purple), and swollen because of the injury. I don’t think she needs to go to the ER for that. From personal experience, I suggest getting a nurse to put on a splint-like thing to keep the toe from moving. If you were on the kupa, I would say go to the clinic, get a Dr to look at it and write out instructions for nurse, and nurse will take care of it. There are private nurses who may do this for you without having to see a Dr (can also judge is there is more going on here).
Disclaimer: Do not take this as medical advice. This was given as friendly help from a non-professional who has experience with stubbed toes.