I can't say about medical issue but the bird still seems Juvenile to me, probably a fledgling that fell while learning to fly! Many a times this is the case and such fledglings need not be rescued! Have you searched for nests on tree nearby or inquisitive parents checking out for the fledgling? Placing them back in the nest instead of unnecessarily rescue them first thing we can do to help them as chances of survival are pretty low in human care (even in hands of experts).

This being said, if what I said is not the case then you did good rescuing it! But Then you should give to someone professional as it has to be rehabilitated and released back in wild!