If i get a tattoo on my side and lose weight will it degrade the art?

Any weight change would change the artwork... it's generally better to get a tattoo in an area that isn't going to stretch/contract over time, and your belly/sides are the most likely area to do this. It might not be so bad if you got it on your back instead, but you might be better off redesigning it as a sleeve or something... Still, if your design is more abstract, it might not make much of a difference. You'll need to get it touched up if you lose weight, though.