Whilst stepping over a chain across a gangway, I caught my foot on it, and the metal post fell over, leaving a wound down my shin. There was no actual bleeding, but there were some small circles of red flesh. It hurts a bit, but when my leg is stationary, I get an accute stabbing feeling as if a pin is being pushed into one of the red blobs. I washed it with soap and water, and then with vinegar. I have used plaster with antiseptic cream. But what can I do to stop the sharp pain, please?