Just because you may have a "mental illness" doesn't mean you're not wrong.

I also wonder, if the tattoos are being looked at as a sign of mental illness and thus a reason not to hire someone.

Personally, if I was choosing between two equal candidates, and let's face it, the type of jobs OP is applying for require no special skills or talent, anyone who can fill out an application can mix a drink or put up a display, I wouldn't be choosing a person with signs of mental illness.

Now I know tattoos, perhaps even in excessive amounts, are not necessarily markers of mental illness but, out OP is marked up and mentally ill, so assumptions woud be correct. Is she the most desirable applicant? Doubt it.

To answer a question, being smart about social change is working within the system, gain trust to spread thoughts, rather than being an extremist.