idence. "Any medical opinion offered into evidence 'is not necessarily conclusive, but is subject to the commission's consideration and weighing."' Farmington Country Club v. Marshall, 47 Va. App. 15, 26, 622 S.E.2d 233, 239 (2005), quoting Hungerford Mech. Corp. v. Hobson, 11 Va. App. 675, 677, 401 S.E.2d 213, 215 (1