The hit has resulted in compression of eardrum
and this is causing pain and ringing sensations in ear.
In such cases one normally finds problems in hearing for few days but eventually becomes all right.however in few cases the ear drum can get ruptured.If the perforation or rupture is small ,it gets healed up of its own in couple of weeks but if it is big then medical intervention is required.
Best would be to consult an ENT specialist
and get the ear examined.
Best of luck