Head injury or Ears ringing or whatever but i will quote a few sentences from OP's sworn affidavit ..that is making my ears ring now!
If his ears where really ringing, how could he immediately shout out to Reeva to phone the police?
A man suffering from sudden loud protracted ringing in his ears due to firing four shots from his powerful handgun in an confined small room, will he be able to maintain his balance and stand on his feet, leave alone be able to shout at the top of his voice immediately, then run around all over his house, open his baloney and scream out for help three times?