Horrible blisters on my baby

EDIT: She has impetigo.

EDIT: NOTHING in our routine has changed. No new food or anything like that. I’m at a loss.

Thursday (07/09) when I changed my 18 month old daughters diaper, all was normal. We ate dinner, got our bed time stuff ready, took a bath. While in the bathtub we noticed a small blistered looking area. We thought her diaper had rubbed it raw. We put A&D ointment on it with a bandaid. I called the doctor the next morning (07/10). The doctor agreed it was probably the same thing. Advised me to continue what I was doing. It seemed to be getting a little better until today. Today (07/12), all day she still only had the one until around 5 pm. I was changing her diaper and noticed another small one on her belly. (The doctor was already closed and I thought it could wait until morning because they were just red places.) I knew at this point it wasn’t her diaper anymore. Around 8 pm she developed two more blisters. They seem to be getting worse. The original blister is the biggest and the worst. I called her on call doctor and WE HAVE AN APPOINTMENT FOR IN THE MORNING SO DONT COME FOR ME. I’m just curious what this could be? Have you seen anything like this before? (The on call doctor advised ointment and bandaids along with Tylenol and Benadryl until in the morning.)

The first picture was what it looked like when we first seen it in the bathtub. It got better until today. The other pictures are from tonight.