For I&D of milia use CPT 10040
10040 - Acne Surgery (e.g., marsupialization, opening or removal of multiple milia, comedones, cysts, pustules)
Some carriers consider this code a non-covered service. In the case of non-covered services, the patient should be advised via a written waiver form indicating that they understand their
plan does not cover this service, that they will be required to pay at the time the service is rendered, and no reimbursement will be forthcoming from their plan.
Medicare does cover this service in most geographic payment localities. However, be careful of the diagnosis code selection and check LCDs
You can also destroy then (CPT 17110/17111). One of the methods of destruction is electrocautery.
You need to select and bill base on a CPT code that most accurately describes the intent of the procedure. Are you intending to treat the lesion via I&D (use 10040) or are you intending to destroy it using electocautery (use destruction code).