Without some pictures, I'm just guessing. Look up "pityriasis rosea" and see how you compare.
If it's pr, then no treatment is necessary and it will go away itself in in a month or so.
It could be many things, some of which are contagious. So, you decide....
There should be minimal itching and no fever or other symptoms. It seldom goes to the face, but can get on the neck.
Good luck.