I've had a few times where I've lied to my therapist (occasionally my pdoc but usually my therapist) and have gone back the next time and said "I lied. My initial reaction was to say whatever but honestly the truth is this and I just wasn't comfortable/didn't think about/felt surprised/whatever and I'm sorry". I've also sent my pdoc emails after appts. saying that and that's the easiest. In fact I just sent her one the other day telling her that I've not told anyone that I've had both hallucinations and paranoia recently because I was paranoid about telling but that I know she needs to know this and so here it was so we could talk about it next week.

Nobody has ever been angry. I am not allowed to lie about suicidal thoughts with my therapist, that's a ground rule from the beginning. But even then the time that I did he wasn't upset. I think they know you aren't intending to lie just to be difficult.