Just a handy tip from your uncle Ghostship: You might want to de-saturate and lighten the tattoo so it looks natural and "under" the skin. You can do this in Photoshop or by using a HSV node. On the old shader I used to use I achieved this look by plugging the natural skin map into the Separate RGB node instead of  the map with the tattoo. If you use a seperate tattoo layer something else has to happen. Notice that the colors and blacks are not deep or saturated, you would not expect that from a real tattoo on real skin. Also make sure that the tattoo layer is using the same bump map and values.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740