I am a bit confused about this tattoo. If the characters are translated individually, one means "wrist" and the other means "white". Except, if they are translated as a phrase, in Chinese, it would mean "wrist is white", and "naughtiness" in Japanese.
腕 = wrist (Chinese); arm (Japanese)
白 = white, snowy, empty, blank, bright, clear, plain, pure, gratuitous (Chinese); white (Japanese)