First of all, you do buff the freshly shaven skin with an emery board, don't you? That helps prevent the itching from ever starting. Since you've already begun to itch, try these steps. If you can't get any silver nitrate, coat the affected area with gel-type dishwasher detergent and wrap it in plastic wrap. Keep it like that overnight and your problem should go away. The whole thing will turn black and drop off by the following afternoon.