You can click on backspace until you go back to the slide that you need. This is actually very useful as you do not need to go to the main document and exit the presentation just to find the slid that you are looking for. There is always an easy way to find the slide that you want.
Being aware of the keyboard commands will help you dominate the presentation of your PowerPoint without much fuss. This way, you can focus on what you are trying to say. It will give you more time to let your audience understand what you are talking about.