And to build off what
@Shyft is saying, it's instructive to consider the difference between Solar medicine and the Malfeas "healing" Charms I just added to the Book of Ten Thousand Scorpions.
Solar Medicine Charms are
exactly what you want to be a doctor. They making you super-good at doctoring. They start with things like "as long as I can stunt up a medical justification, I don't have a problem from having no tools" and move onto things like "by putting lizard blood on the stump of your leg, I can evoke the power of the lizard to regrow its limbs and so your leg will regrow".
Malfeas doesn't do that. Malfeas is a very bad doctor. Malfeas does not want you to be a doctor. You have to come at the concept sideways.
So you start off with Merciless Radiative Therapy, where you go "Right, I have Blight Internalisation Transcendence. My toxic essence is so potent that I can be immune to all Sickness for a season if I go through periodic bouts of extreme agony, because pain makes me stronger. Let's do it to someone else".
So Malfeas' root "healing" Charm isn't like Solar healing. It cures Sickness - by giving them a Sickness that kills any other Sickness they have. And which has a good chance of killing them if you're too powerful, or if they're not in Terrified Awe of you, or if you haven't marked them with a Magnanimous Warding Glyph so they'll have green fire explode in their chest if they betray you. Malfeas spares his servants, but anyone else could well get a more lethal disease from Malfeas than they actually had in the first place. Malfeas cures your sickness by the principles of radiotherapy - ie, "I'm certainly going to kill your cancer. You have more cells than it, so you might survive".
And then everything builds off "nearly killing your patient from radiation poisoning". You get a Training effect that means they get stat boost from
surviving your medical treatment, on the grounds that they had to be a survivor to live through what you did to them. Malfeas is a very bad doctor.
And then there's something which lets you cure their Crippling injuries at the same time as you kill all the diseases in their body - if they survive the radiation sickness - by invoking the power of comic book radiation to mutate people. Solars can just treat your missing eye. Malfeas can't. Malfeas blasts you with radiation, and not only are you cured of all disease that he didn't give you, but then you grow a bright green demonic eye that glows in the empty socket. And you have an Intimacy of Terrified Awe towards him that can't be removed unless someone removes the eye. And you're now a Creature of Darkness.
Solar Charms let you go around, curing the sick and healing the crippled. Malfeas Charms want you to turn your loyal servants into demonic mutants and since they're your servants, they should be healthy and strong. So a Malfean doctor has to go around doing things like "marking people with Magnanimous Warning Glyph" before they start to treat them, so they don't die from the radiation poisoning - and there you're still setting people up to suffer if they attack you, even if you just mean to do it to help them.