| Gauss |
Correct. Poison damage is no different than HP damage in that regard. Once taken it is there until healed in some fashion. Main (low level) methods for healing poison damage: Sleeping it off (base amount is 1pt per ability score) and Lesser Restoration.
Reminder: some poisons require multiple saves to get rid of the poison. The damage does not occur on any round you save but if you fail a subsequent save then you take damage again.
- Gauss