How to Make Tattoos?

Hey so was wondering if anyone had a fix for this. I’ve been trying to make the tattoo and skin material seamless in Blender but don’t know how, any help would be appreciated.

https://gyazo.com/34571388b4083f13b4e1d9aaf0b1d62c

around 2:30 to 9 in this video:

keep the original skin texture and then use a cutout of your tattoo as a stencil/texture