I had a cancerous mole removed from my back too. They did a "wide excision" and took out a lot of skin. They did testing on the mole and surrounding skin and it was fine.
I am not a doctor or anything, but if it were me, I might insist that they remove it after it's treated.
I've been cut a few times for melanomas. I get body checks every 6 months now, and don't bother with the sun anymore. Unfortunately I baked myself all of the time since I was a little girl and it eventually caught up to me.
I'm sure you'll be fine, just keep being proactive
