I take 60 units of lantus (insulin glargine) before bed and 20 units before each meal. can i start another?

Yes, bolus insulin : Lantus (insulin glargine) is a basal Insulin not used at meal time. The 60 units you take at bed time seems appropriate for this type of insulin. Talk with your physician for clarification on the Insulin you need at meal times. (a bolus Insulin should replace the 20 units of Lantus (insulin glargine) you indicate using before each meal). Bolus Insulin is intended to cover carbohydrates you eat at each meal. Various bolus insulins.