The dark spot can be from her skin 'tanning' as dog skin tans dark like that, but most likely based on your description the clippers got hot and the skin in that area got sligthly clipper burned causing the skin to darken and the fur to fall out.
In some cases dogs of this breed get what is called alopecia X and you can read about it here
http://www.veterinarypartner.com/Content.plx?P=A&A=1487
But if the hair is growing back fine then most likely it was a clipper burn in that spot causing the problem.
Hope this helps you!
I took her to the vet and he didn't know what it was. He ran a purple light over it and said there were no parasites (bugs). 'the spot doesn't seem to bother her at all so maybe it's just a shaver burn like you suggested. I was affraid it might be cancer. but I don't know anything about that. I'm just worried about my little girl shes everything to me.
Thanks
Linda
The purple light (black light) shows there is likely no ringworm infection which is good.
If the hair grows back great then you know it was probably clipper burn that impacted the follicles in the skin.
If it does not grow back you might want to consdier using melatonin as the above article about alopecia in my first answer suggests though of course you should discuss it with your vet.
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics