There is plenty that can be seen. The effects are what is seen, not the magick itself (unless you can see, hear, and/or sense energy/spirits which most of us can to some extent or another).
I had a painful cystic ovary that would flare up every few months for years. It was making me feel very ill because, as the doctor explained, the cysts would leak and the fluid would reabsorb into my body. There was no need for surgery, but it was a burden. My husband performed a healing on me, and afterwards, I felt instant relief, the pain was gone. I've never had them bother me again. It's been about seven years since he healed me.
That is just one example of countless ones I could give you. But I don't like sharing such things, nor do I ever boast about my own work. It is sacred and it isn't us alone that does such things, we should always give credit to the powers that help and guide us.