Medicine Kit of Placebo

Wondrous Item This item has 10 charges. As an action, you spend a charge to make a Charisma(Deception) check contested by the Wisdom(Insight) check of a willing creature within 5 feet. If you succeed, you provide them 1d8 + your charisma modifier in temporary HP.
If the target succeeds, they are immune to this effect for 24 hours. The item regains 1d6+4 charges at dawn (max 10). Uncommon

This medicine kit, rather than containing conventional medical supplies, contains a variety of useless cure-all's, scented oils, and purposeless tools, imbued with the power of suggestion. Using this kit requires charisma rather than skill, and your ability to heal people with it relies on their acceptance of your false reasoning.

My experience with the placebo effect within my experiments all seem to vary wildly. Patients that came into my lab with terminal diseases have recovered completely with only their own willpower. However, healthy patients don't seem to respond similarly when I ask them to health themselves from fatal injuries I inflict on them. It's fascinating.
— Kormak Firahel, Scientific Method Enthusiast