What Causes Rash On The Leg And Back?

My daughters friend is 15 years old she has had flu like symptoms for the last 5 days and this morning she woke up w/a rash on her legs and back. her mother does'nt seem to be concerned enough to take her into the doctor. what do you think it may be and should she get medical help for it? and wich one of you gives a shit enough to tell me for friggin free, are you kidding me.