Vivisectionist

When you choose this archetype at 3rd level, you gain proficiency with the herbalism kit, the poisoners kit, and the medicine skill. If you are already proficient in medicine, your proficiency bonus is doubled for all check made with it.

Additionally, when you make a medicine check you can add you dexterity modifier to the result.

Surgical Precision

At 3rd level your anatomical prowess lets you exploit openings in an opponents defense to inflict a debilitating injury on them.

When you deal sneak attack damage on your turn, you can choose to decrease your sneak attack damage to inflict an Injury. If you do so, the target must succeed on a Constitution saving throw (DC equal to 8 + your proficiency bonus + your Dexterity modifier) of suffer one of the effects detailed below. An Injury persists until the start of your next turn.

You can decrease your sneak attack damage by 2d6 to inflict one of the following Injuries:

• Hamstring: The targets speed becomes 0.
• Gut Shot: The target has disadvantage on attack rolls.
• Skull Crack: Attacks against the target are made with advantage.

Steady Hands

Starting at 9th level you can use the bonus action granted by your Cunning Action to use a healers kit or make a medicine check to stabilize a dying creature. Additionally, when you stabilize a creature you can have them recover a number of hit points equal to your Dexterity modifier. 

Twist The Knife

Starting at 13th level your increasing skill allows you to cause even more grievous wounds. You can now decrease your sneak attack damage by 5d6 to inflict one of the following Injuries.

• Sever Tendons: The target becomes incapacitated
• Eye Gouge: The target becomes blinded
• Puncture Arteries: The target takes 2d4 necrotic damage for every 5 feet they move. They take this damage even on forced movement. 

Lingering Wounds

Starting at 17th level your injuries become harder to recover from.

When the effects of an injury would expire at the start of your turn, the target must instead make another Constitution saving throw against your Injury DC. On a failure the injury persists until the start of your next turn.