The film follows six individuals, including major league ball player Ben Petrick who report chronic symptoms, which they attribute to persistent Lyme infection.

The second half of the film focuses primarily on state medical board investigations of Joseph Jemsek and Ray Jones, two physicians who prescribe long-term antibiotics for chronic Lyme disease, a practice generally recognized to be dangerous and without provable benefit.

[7] The final act of the film focuses on Connecticut Attorney General Richard Blumenthal's antitrust investigation of the IDSA Lyme disease guidelines.

[11] The case was described in Forbes as "intimidation" of the medical community by the Attorney General,[5] and in JAMA as an example of "elected officials advocating for health policies against the weight of scientific evidence.

The critical consensus reads: "A scathing indictment of the American medical system, Under Our Skin is timely, frightening stuff.