Thank you so much! I feel like the Starfleet doctors can be really dependent on their tricorders, so not having something turn up on that would be hard for them to believe.

There's both. The tattoo marks the placement of the chip, as I'd imagined it to not necessarily be in the same place for everyone. People that went along willingly might have had it in a different spot than Jim, who I imagined struggling and fighting so he was pinned down with his hand held out. In my head. :P