broke my foot kicking a wall, doctor said it was bruised, x-ray said it was broken, tried to walk on it and caused more damage.
several fingers broken (over a couple of years of playing cricket badly) doctor said just bruised, x-rays said otherwise.
broke my wrist playing football badly, similar story.
only one way to be sure, especially if you think there maybe any displacement.
However, with my hand related injuries, I have left A&E with the same dressing which i went in with.