The time it takes for a knee skin injury to scab over depends on the extent of the injury. If it is just a general minor epidermal injury, it can scab over in 3-5 days. If it is a deeper skin injury, the scabbing time will take 1-2 weeks. First of all, the local area needs to be cleaned, and then disinfected with iodophor, you can apply Bactroban to prevent infection. Infrared physical therapy can be used to help the wound scab over sooner. Avoid contact with water as much as possible after the knee injury to help it scab over as soon as possible. Take rest and avoid excessive knee flexion for the time being. If the local swelling and pain are significant, it is also necessary to pay attention to the possibility of combined fracture, and timely improvement of the knee X-ray will help to determine.