Slight pain from a wound is normal, due to the wound directly or indirectly stimulating the nerves within the normal skin, which causes pain sensation. Painful wounds should be ruled out if there is any septic infection of the wound, poor healing, fatty liquefaction, or subcutaneous effusion. The skin of the wound is locally red and swollen, and there is an elevated fluctuating sensation underneath, indicating that there may be inflammatory exudate, liquefied fat, or pus accumulating underneath the wound. In this case, the stimulation of nerves by the fluid itself as well as the effect of tension of subcutaneous fluid, pulling on peripheral nerves can cause strong pain at the wound. Otherwise, not only the pain can not be relieved, but also increase the chance of infection, resulting in increased pain, delayed healing or poor healing of the wound.