Confirmed yet? My view of the damage might be wrong though I never used the jutsu myself so never had the time to confirm. When I looked at it again, it might just be x is the number of turns the poison stays in the body without removal so if it stays in the body for two turns, then it's 20x2.
The next jutsu is a huge one which I think you'll like to use.
(Dokuton: Doku Hebi Rendan no Jutsu) - Poison Release: Poison Hydra Barrage Technique
Rank: S-Rank
Type: Offensive
Range: Short-Long
Chakra Cost: 70 (-20 per turn)
Damage Points:N/A
Description: Using the users blood as a template, this technique creates a gargatuan, 10 meter tall Hydra, completely made of thick poison. The user will draw blood in one of his palms and do 3 handseals (Hare, Ox, Tiger) clapping his hands and opening them. As he does, a thick guey orb of poison falls to the ground. As it touches the ground it expands rapidly and seemingly out of control into a gigantic 3 headed Hydra. This enormous familiar will be entirely made of either a generic poison (which will cause increasingly severe muscular pain, sensory numbness and damage if absorbed through the skin (30 damage per turn, effects last 5 turns after exposure), death if the poison is vaporized and inhaled) or a unique poison of the user (requires the user to have a liquid custom poison approved) and will be able to act and move through the users command. The enormous familiar can regrow body parts (if the user pays 20 chakra points) if attacked by techniques bellow S-Rank, each attack creating a new head. It not only can attack a target physically by making contact with it (it can move, stretch, deform, etc in various ways to attack the enemy in a freeform manner) but can also shoot from each of its heads a C-Rank bullet of the poison its made off (using this ability counts as a single move). The drawback of such a technique is sustaining it which drains the users chakra but also his focus and stamina.
Note: Can only be used once every 5 turns, lasting 4 turns each time
You simply make a Hydra made of poison. Simple but immensely useful.