First through fourth grade drama students started the year playing drama games to work on collaboration and improvisation skills. This week we defined the word "improvise". Before defining the word, I asked students to write what they think it means to improvise when you forget your lines.
Richard is right! You should make something up that is as similar to your lines as you can remember. Alexis suggested that it means to close your eyes and visualize your script in your mind. Whatever you do, you definitely shouldn't panic and run backstage.
Relax and improvise. Make something up and keep going.
Fake it till you make it!