Sorry to hear of your 16 year struggle.
From what I know about aneurysms, the slap to the head would not likely be a cause. The congenital weakness would need to be there first. I have an 'minor out-pouching' as described by the radiologist but it has never been a problem despite my many bumps to the head. Imaging for my concussion caused symptoms found this abnormality.
More likely a high blood pressure event, possibly brought on by stress or excitement caused the weakness to blow.
Either way, not more slaps to the head.
My best to you.
Mark in Idaho
"Be still and know that I am God" Psalm 46:10