The troubles of the young are soon over; they leave no external mark. If you wound the tree in its youth the bark will quickly cover the gash; but when the tree is very old, peeling the bark off, and looking carefully, you will see the scar there still. All that is buried is not dead.
No one likes having offended another person; hence everyone feels so much better if the other person doesn't show he's been offended. Nobody likes being confronted by a wounded spaniel. Remember that. It is much easier patiently -- and tolerantly -- to avoid the person you have injured than to approach him as a friend. You need courage for that.