annabody67 I'm sorry too that you're going through this.
Is the needle near the nipple that you're concerned about a dye/radioactive tracer injection?
I had a radioactive tracer injection and a hook wire insertion in the morning before my lumpectomy and sentinel node biopsy. That morning was a bit of a blur, I had a few tears but the people looking after me were caring and kind, took things slowly.
From memory there was a pinch on my breast - I'm pretty sure it was a local anaesthetic first before they did the radioactive tracer. I didn't experience pain, I just had to remind myself to keep breathing and stay relaxed. They put me through a machine to do imaging and they drew marks in my armpit to show the surgeon where the sentinel nodes were (though they said the surgeon rarely uses their marks because they use a Geiger counter).
For the surgery itself I had general anaesthetic.
It's good to tell the medical people if you're feeling nervous. They have done these procedures many times but they will try to adapt their approach to you e.g. if you want more information, or more distraction, etc.