How do you know when a stress fracture has healed?

My 11 year old daughter suffered two stress fractures in the top of her foot back in May. It is now late July and she is still in a lot of pain and still on crutches, unable to bear any weight, even in a boot. The orthopedic says it is because she needs physical therapy and that she should be healed by now. Her pain has not changed at all. She still cannot bear any weight. She has missed girl scout camp and a trip to see her dad due to all of this. She is motivated to feel better. Everything that I have heard about a stress fracture is that you let the pain tell you when it is healed. She is still in pain. I take her swimming as often as I can to try and keep the area loose. She is a kid and could have re-injured. I'm bringing her to our primary care physician this afternoon for more direction. I need to know what to ask for and what to expect.
What is your experience? Should I make her push through the pain, without a follow up MRI, and trust the doctor that she 'should' be healed? Or do I continue to treat her as if it is still fractured, and risk her starting back to school on crutches?
On a side note, she takes a long time to get teeth in. She lost her front four and finally got them all in 2 years later. I mention this in case it is an indicator of slow bone development? Might be a reach?
For those of you who are curious as to how it happened- she was the victim of a hug gone wrong. Yes, that is right, she's been on crutches all summer because of a hug. A friend of hers (who is a foot shorter than she is), picked her up, swung her around, lost balance, and then landed on her at school, bending her foot backward. That's the kind of luck this poor child has.