My personal opinion, I think it depends on what forgiving represents to you. Will it be apt to reopen pathways that allow future lying? Because that's no good for anybody.

I think it's far more important to make sure you forgive yourself, because when people screw us up by lying to us the worst part of it is how it can degrade our trust in ourselves. When we trust and get punished for it, it gives us the message that we can't trust ourselves, and it can take some time to rebuild our trust in ourselves. So those who have negatively contributed to degradation of self-trust, and aggressively, are way down on the list for me, for who I'm worried about forgiving. I don't harbor anger, but I'm not going to be a party to anyone's game-playing when important trust is on the line, and with a compulsive liar it requires vigilance that forgiveness does not always support.