This was a split-face , randomized study evaluating the use of three injection techniques - ( i ) deep bolus injection into the mid - to lateral cheek , ( ii ) local mid - to deep dermal injection into the nasolabial fold , and ( iii ) both deep injection into the mid - to lateral cheek and local mid - to deep dermal injection into the nasolabial fold - for the treatment of moderate to severe nasolabial folds .