Can you please explain the gooey white stuff inside my open wound?

Self protection. When our bodies sustain an injury, the immediate response is inflammation (red, hot, tender swelling).This is the body increasing blood flow to the injury to bring healing factors to the area and also the veins expand to carry bad stuff away. It also tries to cover the wound to protect it from further injury. The white stuff (fibrin) is used to create a protective cover for the wound as it heals.