At level 3 you gain proficiency with a Poisoner's Kit. You do not have to have the physical kit on you in order to benefit from this as long as you deal 1 damage per level to yourself, using your blood as the physical components of your concoctions. You may only have a number of poison doses prepared equal to your proficiency bonus and you must save against each of these when you take Bludgeoning/Crushing/Falling damage to avoid breaking their containers and exposing yourself. You are only adept at creating contact poisons, which take effect on the target's next turn.
Crow Touch
At level 3 you may use your Cunning Action to perform a Sleight of Hand check in order to safely expose a target within 5' to a contact poison. You may also attempt to "splash" this on more than one target within range but you must yourself make a Constitution save with Disadvantage in order to escape the effects yourself.
Toad Touch
At level 9 you gain proficiency with an Alchemist's Kit and gain the ability during a short or long rest to convert a magic potion to take effect on skin contact.
Moth Touch
At level 13 you may create alchemical poisons that cause the target to be affected as if they were a different category of creature, such as Undead or Infernal or Elemental. The target will be affected as if they were the type of thing in question.
Collector Mentality
At level 17 successful check of both your alchemical and poison use and access to the corpse, willing essence, or unconscious access to a monster will allow you to distill a monster ability such as mummy rot or petrification into one of your contact poisons.