Any wearable needs a power source, and any prototype is going to involve wires and breadboards that are not by default hermetically sealed. In the event your moist skin provides a lower-resistance path for the voltages involved, you might find your project (and self) dead.
Lithium batteries are extremely unforgiving, as well. Try to stick to a single cell, and if you need to put in multiple cells, put safety circuits on them.
It wasn't long ago (January 29th) where a man was killed when his e-cigarette exploded and part of it shredded his carotid artery.
Edward Thorp's 1961 wearable roulette cheating device started arcing when the young women wearing it started to glisten a bit too much in the sultry Vegas casinos.
I'm sure your prototype will be way cooler if it doesn't cost you an eye (safety glasses), your skin (from burns or explosions), or body parts of your intrepid friends and loved ones.