I'm not saying it's definately a healing reaction but I wouldn't rule it out. All kinds of symptoms can crop up when you're cleansing. I've never had exactly what you describe, but I have had reactions where my skin felt sore to the touch and my clothing brushing off the area really irritated me - I kept going and it got better though. Now that I think of it, my jeans waistband was one particularly sore spot, that and the skin on my arms, like sore goosebumps. I'm not sure about the significance of it being on the area of your body that its on, maybe someone else can answer that for you.
Try to avoid donuts - and chinese if you can... I know it's hard, I had many, many backslides when I started to improve my diet, and sometimes I still indulge in a treat but I try to keep them as few and as far between as I can. If you do cave and have something bad sometimes, just put it behind you and continue on with the good stuff, don't beat yourself up about it.