I got smoked in the temple by a knee during jiu jitsu. I felt immediate pain that immediately subsided. No sypmtoms, so I kept rolling. When I got home, I realized that was pretty stupid and I started remembering hearing about people dying from minor blows to the temple. I stayed up late to make sure I was ok but still no headache or any symptoms. After several days of no symptoms, I eventually got a mild tension like headache that lasted for 3 weeks and felt generally run down, like I had just woken up all the time. And then I was fine. Long story short, head injuries are bizarre.