What Causes A Cluster Of Red Itchy Bumps On The Thighs?

I'm 21, 120 lbs 5'7" female. I first noticed a small, itchy bump on my thigh in October. I thought it was a bug bite until I scratched it and it burst open. They next day there were 4 small blisters in its place. Within a week or so, the 4 blisters were healing. One night I accidentally shaved over them. The next day there was a cluster of red itchy blisters. It had spread. I put a band aid with ointment already made into the band aid on the blisters thinking the ointment might help. Every time I took the band aid off I noticed the blisters were bigger, so I just took off the band aid. Its stopped spreading but didn't go away. And after the initial itching the blisters started to hurt. I went to the doctors and the Dr said I had impetigo. She gave me antibiotics to take by mouth and Mupirocin Ointment. Taking the medicine and applying the ointment made it slowly go away within 2 weeks. I think I was misdiagnosed because 2 days ago (only 2 months later), when I woke up I noticed a smaller than a dime sized cluster of the same blisters in the same spot. I rubbed the same Mupirocin Ointment I thought helped me the first time on the cluster. The medicine said 3 times a day. I applied it twice and every time I looked my rash was getting bigger. The ointment irritated it, so I stopped putting it on. It stopped spreading and is now starting to hurt again. I searched impetigo and the pictures looked nothing like my blisters. My blisters looked closer to a picture I saw on Wikipedia of shingles. Any idea what it could be ? Thank you for any help