I doubt he'll see it as you having lied - people share things in therapy at different rates and you hadn't recognised it yourself so I wouldn't worry about him thinking less of you. There are loads of things I've half mentioned, denied or just refused to speak about - and an issue i felt I had lied about in T but it's always been open for be to revisit things throughout therapy.
It sounds like you're in early stages of therapy and it may just feel too soon for you to share, or you may be ready to talk about it. Don't worry about him thinking you've lied, it'll be fine.