jackstruble I think cages make a great reminder in that regard, but I am not going to recommend you to wear one at your age, particularly if you are having pain wearing it.
Use it however you like. You may find that it gets easier to wear over time, but do not expect to be wearing it all day right away without major discomfort (and if you experience major discomfort or pain, take it off to give yourself time to heal).
And definitely try to work on your willpower without it as well. You may find that the cage reminds you more of your body parts themselves than your commitment not to touch them.
And by all means, do not give the key to a stranger, especially while you are still a minor.