On Page 77 of Bend, Not Break, Fu Ping describes what happened after passing out during a beating and rape attack:
The next thing I remember, I woke up at the NUAA health clinic. A kind nurse told me that I had sustained "deep cuts, a broken tailbone, and internal injuries." It had taken more than forty stitches to close the wounds. I carry the scar to this day.She was then sent home to recover for herself, which appeared to consist of purely bed-rest.
Since Fu Ping has repeatedly stated that she still has the scar from that attack, we can believe that she was once beaten and suffered knife cuts over her body.
The questionable parts here are the other injuries or the lack thereof. There is no mention of any injury of sexual nature, which is quite unusual for a 10 year old being raped by a gang of 10 to 12 boys.
NUAA was not a very big school and a health clinic is not a hospital. As "xgz" had previously pointed out, it is unlikely that the clinic would possess an X-ray machine to diagnose broken bones. The fact that she did not get transferred to a hospital for treatment seemed to imply that her injuries were only superficial ones.