This provides some very nice ideas for magic tattoos. The comments from Tyna are a nice touch, though the font used is a little bit too small.
My biggest concern (and the reason why I didn't give a 5 stars rating), is that the description of the effects themselves, while generally understandable, don't always follow the 5E format and jargon. This causes confusion in some cases, such as for the Aegis Tattoo (where it is not described which condition can trigger the reaction). Tattoos that have prerequisites should probably necessitate attunement, as this is the way 5E deals with prerequisites for magic items. In other cases, the tone is very direct and abrupt, and doesn't give a 5E feeling (such as the Mark of Protection, in which there is a sentence without subject, or most of the cursed tattoos, that use "the wearer" instead of "you", or the use of the abbreviation "mins" instead of "minutes"). This gives the feeling of a draft rather than a finished product.
Mechanically, most of the effects herein are interesting and balanced, and fit very well within the Scarred Lands mythos. A few seem to be overpowered (effects that grant advantage on attack rolls should probably last for 1 minute) but these are rather rare.