Beat cream cheese with a mixer. Add in sweetened condensed milk and beat well to combine. Using a zester, zest two or three lines. Add lime zest and lime or lemon juice to mixture, and beat well. The mixture may be a bit lumpy at first, don't worry, just beat until smooth and creamy. Poor mixture into pie crust. Place in refrigerator for at least two hours. Slice, serve and enjoy. Store in refrigerator.