The wound forms a white cortex, a condition that needs to be determined by how long the wound has been forming or if the wound is reacting with redness or swelling. If the wound has been in place for a long time and is dry, there is a chance that it is a scab, which is a normal scab and generally indicates a reaction to the wound growing back. However, if the wound is recently formed and there is a white covering and redness on the surface, it is possible that necrotic tissue has formed as a result of some infection on the surface. Once these necrotic tissues appear, you need to go to the hospital for debridement and antibiotic treatment if accompanied by redness and swelling. In addition to local disinfection, oral antibiotics, such as oral roxithromycin, are also needed.