Heat olive oil in pan over medium heat. Saute shallots and garlic for 30 seconds. Add crawfish and creole seasoning. Saute an additional 1 to 2 mintues. Add cream, hot sauce and Worcestershire sauce. Bring liquid to a boil, then reduce to simmer. Simmer the cream until it thickens and reduces by half, about 5 mintues. Add butter, salt, pepper to taste. Fold in green onions and serve over already cooked fillets.