I Found this at busywomen's fitness.com:
"What isn't commonly known is whey's historical use as a medicinal food going as far back as the time of Hippocrates. Researchers have now begun to study the benefits of whey protein as a food that promotes more that just muscle growth... Two recent studies show whey protien may have beneficial effects on both the body and mind."
Looks like it won't do you any harm and may actually have benefits.
See what your physio says.
Get well soon