My granddaughter (16 mo) diagnosed roseola or fifths. I have an itchy rash on arms and neck and had fever blister. Any connection?

No connection. Human herpesvirus 6 (HHV-6) is the most frequent cause of roseola.?Roseola classically begins with three to five days of fever that may exceed 40ºC (104ºF); as the fever abates, a blanching macular or maculopapular rash develops, starting on the neck and trunk and spreads to the face and extremities. It is self limited and benign. I do not believe your symptoms are caused by Roseola!