I caught this from an old person with "Shingles" when I was working as a disabled transport driver. I helped the man on a Wednesday and by the Friday of the following week I had an itchy spot on my forehead. By the following morning it was only too clear what was happening.
I had not caught this as a kid so got the rash and other symptoms. I did not feel bad at first, but three days after the first spot appeared I was fatigued, like having a cold without the blocked nose. All I wanted to do was drink water and sleep.
The rash gradually subsided and I went back to work after a fortnight. This time off was advised by the doctor to prevent my passing it on to others; I was feeling fine again after about five or six days from the first spots.
If this should happen to you DO NOT scratch the spots. You not only cause a route for further infections when your resistance is low, but also could end up causing lasting scars, especially on the face. Leave alone and the spots will heal completely, however hard it might be to resist the temptation to scratch.