You shouldn't worry about this; God knows your heart, and He knows you weren't intentionally telling a lie. If you haven't already done so, go to your neighbor and set the matter straight. Not only do you want to avoid misleading your friend, but you want to keep your friend from passing on false information to others.
However, something you said elsewhere in your letter made me wonder if your real problem was gossiping. No, you might not have been telling an intentional lie - but were you talking about other people in wrong ways? The Bible warns us against the dangers of gossip; not only do we risk passing on false information, but we easily tear others down. The Bible warns, "A perverse man stirs up dissension, and a gossip separates close friends" (Proverbs 16:28).
Remember: Even when something is true, it isn't necessarily wise or right to pass it along. As the Bible says, "There is a time for everything ... a time to be silent and a time to speak" (Ecclesiastes 3:1, 7). Always ask yourself not only if what you're saying is true, but if it is helpful. Would you be embarrassed to say it if Jesus were standing with you?
Nothing can get us in trouble quicker than our words - and yet nothing can be more helpful and encouraging to others. Let the psalmist's prayer be yours: "Set a guard over my mouth, O Lord; keep watch over the door of my lips" (Psalm 141:3).