Begin a journal or memory book if you are prone to physical phenomena. Make a self hypnosis tape to counteract the post hypnotic suggestions you have been given not to document or even remember the experience. Any time you find unusual makes on your body, photograph them. BE sure to take two photos. One photo should have a ruler next to the mark, preferably metric.
Coins are uniform in size.
Last but not least, if you have pets, be sure to note any unusual behavior they are exhibiting. Be on the alert for them oversleeping or seeming to be disorientated or drowsey. Note the time and date. This may coincide with your abduction as anxiety in the animal may. Fish seem prone to anxiety verses drowsiness.