An acoustic panel (200) for an aircraft nacelle (100) may comprise a perforated first skin (220), a second skin (230), and a core (210) sandwiched between them. A damaged portion of the perforated first skin may be removed. A fiberglass ply (510) may be coupled to the acoustic panel. A pressure differential may cause the fiberglass ply to form dimples (515) within the perforations (325) of the first skin. The fiberglass ply may be used as a template to drill holes in a replacement patch (400).