When the immunity of the body decreases and when you have oral herpes, the herpes will penetrate into the surrounding skin mucosa after the blister is pierced, causing more blisters to be produced, resulting in erosion and crusting of the wound surface, and in severe cases, pigmentation. In the case of oral aspergillosis and other herpetic diseases, the blister will tear off a large area of the surrounding mucosa and expose a large area of mucosal trauma, causing painful chewing and eating irritation. If you have to pierce the blister with an unsterilized tool such as a toothpick, it can cause bacterial infection of the trauma, and in severe cases, septic changes can form, affecting healing.