Hey Lost. There is no such thing as too much detail in a Tattoo. The size of your tattoo dictates how much detail you can have. If the tattoo is small with a lot of detail it will look a mess in years to come as the lines do thicken with age. A five pointed star 6-8mm is possible however from a distance won't look like a star due to size. It can be done thats why there are different size needles that suit each piece of art that you do. As for scarring, It depends on age of scar and size and can be worked around, This comes down to placement. If you have execma and conditions of a like it would not be possible, dry skin or heat rash or fungal skin conditions are tattooable, Also a good tattooist does not have to be in a studio, As long as needles are new and disposed of after every client, equipment is properly cleaned, the area you work in is sterile, you have proper medicare before during and after tattoo, disclaimer forms. I can go on but wont bore you. Oh and uses good quality ink as a good artist can also be judged by the quality of the black ink he/she uses as there are many so called black tattoos that are more blue and faded due to lack of effort/quality.