This is 100% true. My tattoo artist also said I had thick skin and had do go over the lines. A previous artists said the needles weren’t going through my skin and pushed harder - causing a blowout. This skin can be found on places other than your extremities as my tattoo is on my ribs. The successful tattoo artist has been working for over 10 years and has only encountered it a couple times, BUT IT IS A THING.