The body protects itself, and the same happens in the mind. It occurs sluggishly and imperfectly, a bad job done by indifferent craftsmen, but within minutes an accretion of defence mechanisms starts to form around the trauma, blunting its edges, eventually sealing it away inside scar tissue. Like a sliver of glass buried deep in a cut, the event will never go away, and often a movement will cause it to nudge a nerve ending and burn like fire for a while. However much it hurts when that happens, the last thing you want.