Maybe it's the area of the body you are working on that isn't healing as you'd like? I find that rotaries are better for some areas than others. Very squishy areas like sides, near armpits, stomachs are great for using a rotary, whereas thin-skinned areas like ankles and sternums are really easy to overwork, as the machine hits hard, and I find I have to be much gentler. I also find at times that a larger configuration doesn't give me the same color saturation that using smaller groupings can. I take it you've been using larger configurations all along, though?