This term I've been taking "Intro to Pokemon Care", which is as it's described. It's super useful for fieldwork and for taking care of Pokemon during conservation efforts.
Miriam, the school nurse, teaches the class, and lets us take care of her Toxapex, treating its battle wounds (that said, poisoning is surprisingly uncommon among her students).
The best, most consistent method that we've beenising for healing Toxapex's injuries is a poison bath. We quite literally bathe Toxapex in toxic chemicals and waste, and it actually works to heal the wounds cleaner than if we were to use standard Potions, which is super interesting. See, normally wounds can scar when they heal naturally, which isn't really a problem, however it can lead to discomfort in certain conditions, such as wider or deeper cuts or scrapes. Potions accelerate the natural healing process, which can cause more scarring and further discomfort. It's great for a quick fix for most wounds, that's why they're so often used (think like alcohol and a bandage. It's no miracle, but it'll do).
Poison types, however, naturally absorb poisons into their body, and can metabolize it. Metabolizing it breaks it down, and certain proteins are restructured and sent to repair wounds and cuts, which is, somewhat miraculously, a very common evolutionary trait of basically all Poison type pokemon, and even some non poison types. This process can take a while, anywhere from an hour to a few days, but the wounds always heal like magic.