Some thoughts on Force-healing on both sides of the Force:
When you think about it, Force-healing (and indeed any kind of magical healing) is at once a very natural and a profoundly unnatural thing. On one hand, it’s returning a body to its natural, working order. On the other, it’s reaching into someone’s body and controlling the flesh, regenerating so many cells out of nothing that it’s almost a bending of reality.
And I feel like this would influence the underlying philosophies of Light Side and Dark Side healing. To a Light Side healer, Force-healing is a warm, soothing hand, urging all the damaged parts to settle back into the way they used to be. It’s a gentle nudge to the body, right at the cellular level, speeding up the natural healing processes a thousandfold. Light Side healing is an act of undoing - reversing damage, taking away the broken and jagged parts until everything’s whole again.
Dark Side healers look at it differently. Regrowing torn organs, mending cut flesh, regenerating cells - all of that should be impossible. So they’ll damn well do the impossible. They’ll twist reality itself to bring their patients back. A Sith healer’s touch is as warm as a Jedi’s, but it’s a different kind of heat, it’s that burning ache you get when you care for someone so much that it hurts. A Sith healer’s touch is a fierce passion that forces your body back together,.
That kind of passion only comes with complete conviction in what you’re doing. So Sith healers need to really, really care about their healing - whether that’s just ‘I care about myself/my cause so I need my allies in working order to support me’ or ‘I love this person and refuse to lose them.’ The more you care, the better you heal.
I’m not sure how this might affect their abilities in practice - possibly Light Side healers can more easily heal minor injuries and illnesses, because those are simple to remove from the body, while Dark Side healers find it harder to get worked up enough about such things to heal them. No headaches, backaches and colds if you have a Jedi healer handy. Dark Side healing, though, would probably be faster, and better at healing massive injuries that people should rightly die of - because a Dark Side healer refuses to hear that anything is impossible.