Hello, I'm A 42 Year Female And I Have Never

Hello, I'm a 42 year female and I have never so much as had a pimple on my body.. I first noticed a oval shaped red patch on the top left side of my breast . A few days later there more red patches on my trunk of my body. I did go to the doctor and they said it was Pityriasis Rosea.. It seems to be getting worse on my front and back. They do not hurt or itch but just the look of them is scaring me.. I look like I have chicken poxs.. They are also on my inner arms but not my legs or my face.. How long will this last? Do they just really go away all are there own??