FSFB is Full Service Food & Beverage (i.e. sit-down restaurants).
A Food and Beverage Handler works in the backstage areas, like kitchens and stock rooms. You receive deliveries, verify quantities, and stock coolers and shelves. Rotate stock/inventory, check expiration dates. Also cleaning and organizing. Sometimes running errands for cooking staff, like to get emergency items from the central warehouse.
Since you wouldn't be on stage, in front of guests, they may be a little more flexible with the visible tattoo. If you were to have an on-stage role, like as a waitress or QS employee, you'd have to wear long sleeves for sure to cover it up.