Some bleeding may be present. This shows that there is good blood circulation to the area, which helps healing. Increased redness around the sore or black areas starting to form. You develop a fever. Can be life threatening.
Infection can spread to the blood, heart, bone.
Prolonged bed rest. Sometimes a scar may remain. A scar is healed tissue but will remain a somewhat different color from the surrounding skin. Scar tissue is never as tough as uninjured skin. If fading occurs in 15 minutes or less, no damage has occurred.