In my Ravenstone story, magical healing isn't always instant. Minor cuts, sure, those close up before your eyes. A broken bone will take at least a few hours to heal, though. And head wounds... well, one character gets a minor concussion and has the same recovery time as a mundane would. Bruises also take at least half an hour after the application of bruise healing cream, though the worse the bruise is, the longer the healing takes.
But yes, magical healing does get used in one of my books to enable torture. Everything has a dark side.
Also, there are conditions in my Ravenstone series known as "magic burn" and "magical exhaustion." Magic burn happens when you channel too much magic through a person's body (usually your own but not always) and the magic starts to damage their nerves and other tissues. It can be healed if it's caught soon enough, but the first step in the treatment is plastering the victim's body with hematite paste and getting them to swallow an anti-magic bolus, to bring their body as close to "zero magic" as possible to interrupt the process. Once the victim has been at zero magic for long enough, you can use small amounts of localized magic to heal any damage, unless they were damaged too much before the magic burn process was interrupted. Truly severe cases can even cause spontaneous human combustion. How much magic it takes to cause magic burn depends on how long you've been a witch and how much of a tolerance for magic you've built up through training. Already, Vedya can do a lot more magic at 15 before risking magic burn than she could at 12. But even at 12, she had more resistance to it than a mid-spectrum witch like Chooli would, even as an adult. (Chooli can't do most spells they teach in magic school; zeer magic mainly works to let zem see spirits and ghosts, and to fight them off if necessary.)
Magical exhaustion is when someone has been pushing their magic too hard and too long, and they're not just exhausted, their magic is exhausted as well. Since magic can keep a person going longer than is normal or safe for them, if someone is so exhausted that their magic was the only thing keeping them going, magical exhaustion can be fatal. (It's not always. Younger witches tend to exhaust their magic before they can reach a fatal point.) The treatment for magical exhaustion is various potions and spells that keep you alive until your body can start to heal, and other potions to aid the healing process.
What's really bad is if you manage to get both magic exhaustion AND magic burn at the same time. The treatment for magical exhaustion is anathema to the treatment for magic burn, after all.
As to trauma and PTSD... the human mind has defenses against magical intrusions, even mundanes. Telepathy and telempathy exist in their magic system, but even those kinds of intrusions can be blocked. Mainly what it means is that changing memories and altering personality traits, or even compulsion spells or other mind control, are so difficult to do that even experts in those magics have to work very hard to get those magics to work. Compulsion spells work best against highly suggestible people, people who struggle with impulse control, etc, but everyone else can usually fight such spells.
Of course, a big side effect of all that is the fact there's no magical solution for PTSD and mental trauma in general. There are some techniques that can help. Memory recorders can help you revisit a memory and get a more objective view of it, since the memories in a memory recorder can be slightly edited to be from an outside perspective. (Artificial dissociation.) That doesn't change the original memories, but viewing the dissociated memories can bring you perspective. Spells and rituals can help you use magic to wander through your own subconscious mind. There may be others, but I haven't really looked into it much in the series, apart from Dalia using the "visit your own subconscious mind" thing in one of the books.