Nature Medicine reports two experiments with 623 lay people and 153 primary care physicians using a fairness-trained dermatology model plus explainable AI, including multimodal LLM explanations. Balanced skin-tone performance improved final accuracy and reduced skin-tone gaps for both groups. Effects of explanations diverged: lay users showed stronger automation bias, gaining when the model was right and losing when it erred, while experienced physicians stayed more resilient and still benefited. Showing the AI diagnosis before a human decision also risked stronger anchoring. The work is task-specific dermatology in controlled trials, so clinics should not assume the same pattern holds for every specialty or explanation style.