About a yr. ago I had a suspicious mole on my back that was kinda big, brown but had a tiny blue spot next to it. It was checked by removing about half of it. It was ok but I was wondering 3 things...

what was the blue spot?

and why on earth did she only remove half of it and not the whole thing? It looks weird..half mole and half scar!

I wonder why she didn't remove the whole thing...couldn't it be cancerous later on?