is there a minimum damage? how...

[Skarg]

Originally Posted by hcobb

And whataboutism poison?

I'd say that a 0-point injury probably isn't enough to enter the bloodstream enough to take effect (especially since we are probably talking about TFT poisons that can take people out immediately).

If the GM wants a poison that must not break your skin at all to take effect (or e.g. Contact Posion), then they could specify that even an exactly-zero damage result will let such poisons take effect.