Perhaps you're thinking of another character in the film? Some characters with markings include:
* Ashitaka: He has a large scar on his right arm from his encounter with the demon boar.
* Lady Eboshi: She has a tattoo of a red spider lily on her left cheek.
* Moro: The forest spirit, in her wolf form, has markings reminiscent of animal fur patterns.
If you can remember any other details about the markings you saw, I might be able to help you identify the character you're thinking of!