Spider bite or shingles?

Three days ago, Ariana complained of extremely itchy bites. She figured something had bitten her in the night. She is our child who most quickly reacts to fleas, bedbugs or other insects. When I looked under her shirt, I was rather surprised to see a swath of blister-type bites from her back, under her armpit and all the way to the middle of her chest.  
I suspected a spider bite since they had seen one in her room and she didn't wear a nightshirt that night because of the heat. They also cause a trail of blisters like this (at least they have in others who believed they were bitten by a spider). 
 We did a little shock treatment on her that first night and it reduced the pain considerably but she couldn't handle more than a few small shocks. She is happier to put up with the pain.
Today, with the line of blisters still looking just as red and with them being just as itchy, I wondered if it might be shingles. Shingles always forms a band and causes an itchy, painful blister type rash. It isn't very common in children as far as I know but when it is apparently it is not often painful like shingles is in adults. I guess we will wait it out and in the meantime, I am treating her with some hydrocortisone cream which gives some relief.