GIMP Add touch-up layer after adding curves layer (and other layers)

Question

Suppose I add several layers in GIMP to make various adjustments such as color corrections and burning/dodging. Once the image generally looks good, I then wish to non-destructively (i.e., without flattening the image) make cloning/healing touch ups to remove blemishes. How can I do this?

More specifically, what kind of layer could I add that would allow me to touch up the subject's skin without losing all the other adjustments?

Answer 1

I usually do that by making a copy the subject layer itself, and use this copy in "normal mode". Depending on the retouch, I add a layer mask on this copied layer so that only the touched parts are used. Any errors on this copy can be promptly made transparent or copy-pasted over from the original.