Don’t know that I’ve seen it done in a movie or TV show. Seems like an easy way to keep them off.
Edit: It occurs to me that perhaps this belongs in CS. If a Mod wants to move it they can, or not.
It depends on the specific rules regarding vampires that are being used in a specific movie. The more traditional approach is that the grounds or the object in question (like water) have to be sanctified. I doubt some tattoo would qualify.
Perhaps blessed ink?
That’s a reach, but I’ve seen stranger things in vampire movies. LOL
Rules vary, but often:
The holy object needs to be actively presented, not just worn.
It’s the faith of the wielder, not the object itself. Sometimes the object itself isn’t even needed, if the wielder has faith.
Sometimes, it’s the faith of the vampire that’s relevant.
Bram Stoker’s Dracula is the genesis for modern vampire fiction, but even that was based on only certain pieces of folklore from certain cultures as well as a few earlier pieces of fiction about vampires. There are lots and lots of different ‘rules,’ and in the many years since it was published those rules have intersected and split and gone all over the place.
So while the answer to this type of question is always it depends (who would win in a fight, Captain America or Wolverine?), it’s even more wibbly wobbly with vampires because there’s not really an ‘original’ set of vampire characteristics to use as a baseline.
I’d agree that “the holy object needs to be actively presented by a person of faith” is a very common rule, but I feel sure I’ve seen or read instances where a vampire approaches a sleeping woman and recoils as he finds a cross hanging on a chain around her neck. Likewise for tattoos.
Need answer fast?
Definitely agreed. If it makes for an interesting story that a cross tattoo does work, then, yes, it works. If it makes for an interesting story that the wearer of the tattoo thinks it’ll work, and it doesn’t, then no, it doesn’t work. 
Is it only a cross, as a symbol of Christianity? I kind of remember some video vampire or expert saying any religious symbol would work if the wearer had faith.
I don’t see why a tattoo, which is a cross made of ink and skin, wouldn’t work. I’ve seen wooden crosses and metallic crosses, probably silver, both repel vampires. Even somebody holding up to random objects or their fingers to form a cross has worked. Why wouldn’t a tattoo work, assuming the faith requirement is satisfied.
I recall a humorous take from (I think) What we do in the Shadows, where it was explained that the vampires had spent centuries encouraging all sorts of silly superstitions just to make it easier to prey on humans.
I’ve definitely read stories where it’s literally any symbol of faith.
That was a plot point in the movie Fright Night; the vampire pointed out that belief was necessary for the cross to work.
True, and there are also explicitly-Christian works where only symbols of Christianity work, as the One True Religion. There are probably also other works where it needs to be the One True Religion, but the One True Religion is something other than Christianity. And there are also works where it’s entirely secular, and crosses work but other symbols (even other Christian symbols like the Ichthos or the Chi Rho) don’t, for reasons purely relating to the shape. Probably most common are works where crosses work, but it’s never explored why, precisely, they work, or what else would or wouldn’t; they just do.
In the earliest Universal movies, it was the cross itself.
In Dracula, when Renfield’s cross accidentally drops into view, Dracula turns away and hides his face. Later in the movie, when people actively brandish a cross, he runs away.
In Son of Dracula, the Van Helsing surrogate says, “It would take too long to explain why they fear it, but they do.” Later in the movie, Alucard has to run away from crosses. If backed into a corner, he gets as far away as possible, and turns to face away from the cross.
In Dracula’s Daughter, the vampires can use crosses in rituals, even touch them. They just cannot look at them.
Which of course brings up the silly question: what if there was a blind vampire? Do they just sense it?
In the TV series Forever Knight, it was the vampire’s own religion that mattered. In one episode, two vampires were discussing another. “The image of the Sun God affected her the way a cross would affect you or me.”
And then there was The Fearless Vampire Killers: or, Pardon Me, But Your Teeth Are In My Neck. A woman brandishes a crucifix. The vampire laughs and says, “Oy vey, girl, you’ve got the wrong vampire!”
I liked that one scene in Dracula 2000 where the guy whips out his cross, and the vampire says, “Sorry pal, I’m an atheist.”
To the premise, the only thing I recall seeing like that was In the Mouth of Madness, but that wasn’t about vampires (and it didn’t help).
My first reaction was to see your character covered in cross tattoos as the vampire approaches. The vampire stops when it’s close enough to make out the designs, and it stares at the little inked crosses, fascinated, and has the urge to count them.
That brings up a thought: A lot of folklore uses the vampire’s (or other supernatural creature’s) obsession with counting as a delaying tactic: Throw a bag of rice at the vampire, say, and it’ll feel compelled to count every single grain, by which time the Sun has come up or the rice-thrower has fled far away. But what if vampires do have the counting-compulsion, but it doesn’t slow them down, because they also have supernatural counting ability? The would-be victim throws the bag of rice at the vampire, and the vampire reflexively says “seven million, eight hundred twenty-three thousand, five hundred forty-two”, and just keeps advancing?
Raymond Babbitt, Vampire.
Rutger Hauer did that in one of his Dracula movies.
What if he holds up a Darwin Fish? And would he have to be an atheist also for it to work?