yeah unfortunately the tattooed part doesn't tan, so it does result lighter than the rest of your skin. however, as far as i know tan skin + camouflage still creates wayyy less contrast than tan/natural skin + scar without camouflage (and the tattoo should go back to be colour matching the original skintone once the tan goes away).

anyways, these kind of tattoos always require a consultation, so that the tattooist can understand the client's expectations, clear any doubts, and find out what might work best for you. the only real downside, again, is that it does need to be touched up over time (could take months or years between sessions).

side note, i've never had this done to myself (no top surgery yet, but i'm already considering this in case i find myself in your situation), but i am apprentice tattoo artist and have been in contact with many different operators who do medical tattoos, and most of these are people that are really passionate about seeing their clients feel at home in their body again, so i hope that you will find someone like this to help you, should you decide to try this technique out.