A brain implant stands for something foreign placed at the centre of who you are. Dream books read it as fear of being controlled, or as a wish to be enhanced beyond your limits.
Has this come up in your dreams before? What was going on in your life then?
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.