A 14 year old girl sustains a steam burn measuring 6 by 7 inches over the ulnar aspect of her right forearm. Blisters develop over the entire area of the burn wound, and by the time the patient is seen 6 hour after the injury, some of the blisters have ruptured spontaneously. In addition to debridement of the necrotic epithelium, all the following therapeutic regiments might be considered appropriate for this patient, except: