Damien, I just figured it out...the black brush wasn't truly "black". That's strange...I reset my brush but hadn't checked that.
And I see you just replied!!! Thank you..I'm sorry to have bothered! I thought I was losing my mind.
Bad content aware fill..instead of cloning I usually just create another layer, move the photo over, add a mask and mask away and then flatten it. (don't kill me if that's bad, it's just how I've always done it).
I have a Mac desktop running latest and Photoshop cc 2015. It is over 2 years old, and has 16GB of RAM. Its SSD hard drive has 75GB free out of 250GB. The last time I shut down was just before posting this thread. I rarely run a cleanup program.
So it's been a while since I've edited and I'd say I am very proficient but I had a baby so who knows anymore....but I still know how to use my layers and brushes!!! I had created a layer with a mask and was just masking out something on the right side because content aware wasn't great and I accidentally went too far over my son's hair..so I inverted my brush to black and instead of going back to the top layer there is now a "GHOST" image...I can just not worry about it and start over and not go that far over but why is it doing this?? I reset my brush tool btw.
(and I'm about 4 months overdue calibrating and my son totally messed with my brightness-please forgive this)