Looking down to the right-hand side can often trigger your subconscious mind to pull up information you are looking for.
I recommend that you do a one-page sketch of your speech that has your main points and details. I do mine in multiple colors so it is easy to follow. Keep the sheet of paper where you can quickly look down on your right hand side to refocus if you forget something in your speech.
Your audience has no idea if you have forgotten something. So you are best to remain poised and continue on as though nothing happened. If later on you remember what you were supposed to share, simply say, “Remember earlier when we talked about the computer system? Well, there is another critical component I’d like to discuss with you.”
Your audience will never know you made an error unless you apologize.