An establishment that primarily sells alcoholic beverages, but does not do extensive preparation of nonpotentially hazardous food or potentially hazardous food, may not need a retail food permit. DHEC issues retail food permits (pdf) to facilities that meet the descriptions of Regulation 61-25 Retail Food Establishments.
An establishment that serves alcohol will need a liquor license, but DHEC does not issue liquor licenses. For that, you must contact South Carolina Department of Revenue (DOR). DOR will determine if the amount and type of alcohol you want to sell will require you to get a food permit.