Hank Skinner and his wife, Carol, are no strangers to pain, having collectively experienced multiple illnesses and surgeries. Hank relies on a fentanyl patch but is now being forced to lower his dosage. (Salwan Georges/The Washington Post) By Joel Achenbach and Lenny Bernstein September 10 at 10:54 AM Carol and Hank Skinner of Alexandria, Va.,…