Why does my tattoo sometimes feel 'raised' and bumpy?

it becomes very bumpy because it is like a scar on your skin. i had one on my back a few months ago and when i got it re coloured, it went all bumpy. i dont think you can do anything to reduce the bumpiness but you could try and see if vaseline will slowly moisturise the skin so it fades a little because the tattoo is bumpy more on dead skin.