Im just starting radiation. Are you using any creams? I am using Miaderm three times a day. Also was recommended Aquaphor,and Cetaphil. I was using EMU oil to get my skin ready in the weeks prior to radiation.
Using gentle soaps without any chemicals in them as well.

Yes, i had redness, swelling and an itchy rash very early on. i was told i could use hydrocortisone- but that it would only help the itching- the rash was there to stay. I used 100% aloe Vera (clear) everyday. In fact, I applied it immediately after radiation each day. I also used Aquaphor at the first sign of any dryness. It is greasy, but I completely believe this helped save my skin. These were the 2 lotions recommended by my Dr. I also swear by the pure lanolin-( used for breast feeding mothers), I would use this for the cracking- I found it works wonders. All of these were a available at Target and another local large grocery store.
And only use gentle soap.