I am diagnosed with several conditions. In general, most people aren't truly interested in an explanation of even just one of these conditions. While a few ask, these people appreciate brevity, with vague descriptions.
One of the ways both parties may profit from such a discussion, if the discussion is going to occur, is to share the ways in which your condition(s) limit you. This may help people with their misunderstandings about the motives behind absences, etc.
I like your tattoo. Its presence prompts interest/questions, as tattoos usually carry special significance for each person sporting a tattoo.
I like the support/advocacy type of an explanation for the semi-colon tattoo.

WC