A clinical recurrence is not required for Mohs surgery.

Mohs surgery is an appropriate method to treat an incompletely excised skin cancer on the face.  Because the margins of the excision specimen were positive for tumor, we would need to assume that if you were to wait long enough, a clinical recurrence would eventually occur, that is visible tumor would eventually declare itself. 

While not an urgent matter, I suggest you do not wait longer than 1-3 months before undergoing Mohs, as the tumor will grow wider, dive deeper and require a more extensive procedure and reconstruction.