To forgive and for it to take effect needs the element of time. But not only time but the decision to forgive, constantly. At every juncture when the wounds remind you of hurt, you decide to forgive. Until your remembrance removes the emotional element of hurt from your memory.
To forgive: the constant decision to eradicate the emotional element of hurt from your memory, because we can never forget. Just like scars. The marks are there to remind us that there was a period that it hurt, but now the hurt is no more.