That would be pretty much the equivalent of saying that anyone who needs a prostate exam or a pelvic exam is giving consent to rape. My body isn't there for a doctor to play with, even if he does need access to particularly sensitive areas to do his job.
No, it isn't. You're equating a temp tattoo with rape. At MOST, I think we're talking about molestation, but probably not even that.
I do think the guy needs a reprimand, the severity of which depends on the distance of the temporary tattoo from the site of the operation. Depending on the setup, the doctor might not of even been aware of quite where he was due to surgical barriers and such. At the very least, there should be some witnesses - you don't perform surgury alone.
This would be a tough one for awarding any damages, I think. It's not like she's in anything other than mental anguish over the tat. It'll probably wear off quicker than the stitches.