I used Gentle Magic for a week. My skin is itchy, and I developed a rash. Should I stop or continue?

If it is irritating your skin, you should stop using it.

It doesn't matter if it is safe for another person, because it isn't for you. Stop using it. Keep the affected skin clean and dry to promote healing. It may take some time for the rash to fully go away depending on how irritated your skin is.