Syringe of Regeneration (5e Equipment)
From D&D Wiki
Syringes offer a much more direct way of getting magical potions into a person's system than simple ingestion, allowing effective healing using a much more cost-effective quantity of healing juice. The syringe of regeneration costs one fifth as much as a normal magical item of its rarity.
Regeneration. By using an action to inject yourself or a willing creature with this syringe, the target regains 1 hit point, and in addition may roll an additional hit die during their next short rest when regaining hit points.
Side effects. The process of sticking a syringe into someone can be an overwhelming shock to their system. When a creature is injected, it must make a DC 10 Constitution saving throw, becoming incapacitated for one minute on a failed save.