I just fell and now have a big knob on my shin. i can walk and the knob has decreased during the 30 minutes since it occurred. should i see a doctor ?

Shin Swelling: You've traumatized your leg which could just be soft tissue injury or even involve the bone, depending on the nature of the fall. Swelling can be inflammation or a hematoma, which is a collection of blood under the skin. The fact that it is going down is a good sign. Elevation, ice, and anti inflammatories in the first 24-48 hours can be helpful for most. Xray can be performed if conc w/ fracture.