not knowing the location of the shingles that is difficult to answer but assuming it is not on his face or around his eyes he can go back to work. shingles on the chest or back can be completely covered by clothing and will not pose a contagious risk to others. if he is comfortable and no longer in pain then it would fine to return to his job.
husband has shingles for one week and on med. crusting over still few blisters. when should he go back to work?