Past President of the National Speakers Association Mike McKinley always says, "Do not worry about minor mistakes when you are public speaking. The audience does not know your script."
If you have lots of good material, it will make very little difference in the big scheme of things if you forget to mention something you had planned to say during your public speaking engagement. Such an omission wouldn't make a BIG difference. Thus, it isn't worth getting yourself so rattled because you left something out that you start a domino effect of making additional mistakes and omissions.
