3 weeks sounds like a long time to still have swelling. I would probably take her to the doctor to have it checked. It may not seem broken, but may be.
I broke my big toe about 8 years ago, and can no longer bend that toe. Most of the time, it doesn't create ANY problems, but if I have a full day of walking (I went on vacation last week and spent 2 full days sightseeing in Chicago), I'll have issues with my foot, knee, and hip if it gets really bad. I must be compensating and not even realizing it. Anyway, I've had it checked since then, and they say it's too late to do anything about it. I really wish I would have taken care of it when it initially happened.