Your tattoo artist will need to know about those skin anomalies; you should show them at the time of your consultation. Your tattooer will let you know if they are comfortable trying to tattoo scars. We will usually just go around moles; if we try to tattoo over them, they bleed a lot and don't always hold the ink. Freckles are usually no problem whatsoever; we can ink right over them with no trouble. Varicose veins are almost as easy. Getting a tattoo can be a great way to cover up a scar: old surgery scars, burns, self-inflicted "cutting" type scars and mastectomy scars, for example. But many scars are difficult to tattoo over, especially if they are raised, bumpy or mushy. (The same thing goes for stretch marks.) If the scars are solid and flat, it is easier to tattoo over them but some scars will not take ink well. Some scars, like mastectomy scars, are fairly dark in color but are usually flat and solid enough to tattoo over and I have done some lovely tattoo work over them. I have tons more information on my Cover Up Tattoos page; go check it out.