Struck by a rock in head - what is the physiology behind such a quick bump?

Question

Hello all! Yesterday while rock climbing I was struck in the face by a rock (ugh what a crappy day!). Anyway, I'm fine no fracture or concussion but I am curious as to what exactly causes such a quick reaction (is it just a massive inflammatory process taking place?) - I had an enormous bump withing seconds where it hit me..... OMG, thinking about it hurts :( .... Ive tried googling this but am obviously coming up empty handed. Any thoughts? Thanks... Oh, and please I don't need any safety tips - this was only preventable by wearing a face shield lol

Answer 1

Very brief explanation: Due to inflammation. And yes, it reacts that quickly.

Long explanation: Read a medical physiology textbook and study the inflammation pathway. It's an entire chapter.