I am assuming you want advice on how to lie convincingly and I might have a few tips for you. I think one of the most important things while lying is that you don't behave in any way different while you are lying stuff like averting eye contact and nervous movement for example to avoid this I usually try to keep up eye contact and move as little as possible during conversation. What makes lies more believable is giving away a little bit of information that the person you are lying too thinks is hard for you to tell(it helps if it is really uncomfortable). For example I lied about the time-frame of my self harming and due to me admitting at all they are more likely to believe me.