I had a BCC on my scalp, unfortunately the way in which mine was discovered etc has left me with anxiety over it all. I was meant to be having a removal of a large skin tag that hadn't frozen off well but the day of the appointment it fell off, so I said "whilst you're there can you remove this thing, every time I brush my hair I catch it and it's not healing." He said it was a build up of skin keratosis or something. He removed it, all good on the healing. 2 weeks later the GP called said I needed to be seen immediately, no explanation, I dashed there alone to be told "so yeah, I had a surprise you have skin cancer, I removed it though so I diagnosed you and cured you all in one. Ohh I did a great job too that's great work " honestly, I was all on my own no idea this was coming and an idiot for a GP preoccupied with bigging up his stitch work.
It sound like you have a good dermatologist so be guided by them, the BCCs don't tend to spread much so you should be fine excision wise. Explain your worries to them I'm sure they'll put them to rest for you.
I hope it all goes well for you, try not to worry xx