This works fairly well, but there's a trick: If you just slap the padding (sold as moleskin; look in the foot care section of the supermarket; Dr. Scholl's is one brand) over the wound, you'll still be pressing on it when you ride. You can buy the stuff in "donut" shapes or in sheets and cut your own so it surrounds the wound, but there's a hole over the owie itself to relieve pressure. Helps moderately, anyway, though after awhile the increased pressure around the wound may start to cause trouble.
When you MUST ride, a local anesthetic (Lanacaine is one) can deaden the nerves, though the damage will continue