The tattoo will scab over. Do not shave over it or scratch the skin until the scab has healed completely. If you pick at the scab, you can pull off the pigment, leaving some areas lighter than others. Be careful when you are able to shave in the area again. A deep cut will leave a line in the color.
Colored tattoos are much more likely to fade than black only ones.
Luckily, the black ink is much better than what was used when your grandpa got his done. They don't usually fade to that weird dark green. But you still need to take precautions, or you could be back under the needle gun sooner than you'd think. If you sunbathe or go out in the sun regularly, make sure to apply a high SPF sunscreen to the tattoo. This will help prevent it from fading as soon.