Impotence in a dream is read less about the body and more about power: a fear of not being able to act, perform or make a difference where it matters to you.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.