Second treatment of Sculptra butt injections left me with an open wound in one injection area (photo)

What is this wound after sculptra butt injection? My nurse practitioner for the doctor that did this says it is just my body healing differently in this area and i will be okay. Why is every other injection area not open ( i have hyperpigmentation and bruises still from first session a month ago and second sessions a week ago). Why did this one area leave this crater and why does it seem like it’s getting bigger and not healing? Thet gave me a firm folding stratemed to help the healing process.