Chain Cilice
This bracelet made of spiked chain is designed to fit around the ankle, wrist, or thigh. While wearing the cilice, you can use an action to speak its command word, causing it to tighten on your skin and dealing 1d6 piercing damage to you at the start of each of your turns until you use a bonus action to end it. If you have the Ki class feature or ki points from another source, such as the Inner Resilience feat (see the Backgrounds and Feats chapter), you regain 1 ki point for every 5 damage caused by the cilice. If the cilice would reduce you to 0 hit points, it reduces you to 1 hit point instead and the effect ends.
If the cilice's effect was ended in this way, it can't be used again until the next dawn.