"A virus essentially obliterated Lonni Sue Johnson’s hippocampus, and she can no longer recall what happened five minutes earlier. Her life has become an endless series of jump cuts."

http://www.newyorker.com/magazine/2015/03/30/an-artist-with-amnesia

Based on Lonnie Sue's experience, I would employ repetition and patterns to try to deliver a message to myself after amnesia. It might work and it might not. I would repeat the message many times in many forms (written, recorded, etc). I would make a pattern that when completed conveys the message (a series of numbers that leads to more numbers that leads to the message). Wrapping the message in emotion and music might help too.