At the beginning of the movie, Lax had a swastika tattoo on his chest. A while later it wasn't there and something else was. I thought maybe it was to show a time before the tattoo but it couldn't have been because of the other tattoos.
With everything that was wrong with this movie, a tattoo is probably not a big deal but if you decide to watch the movie and either get bored or disgusted you can notice his chest and be disgusted with his tattoos.
Because he wasn't really a KKK member and just pretending, it was either temporary or covered up. Simple really.
shareHe was going under cover with one of the white supremist/neo nazi groups and had quite a number of those kinds of tattoos. It helps show a time jump without explicitly saying that it's a time jump.
In the present you'll notice that he covers the one on his chest with tattoo of Jesus and the double bolts on his arm (well I forget what that one was). But he need them to help with his cover and if you notice they're just outlines and purposly done that way so he can cover them up later.
You're supposed to be disgusted with the tattoo and what he 'has to do' to help bring down the organization. That's part of the reason he has a weird connection to Herman.