How deep is the wound? If it is deep, then it is concerning for tetanus (lockjaw). Tetanus is a serious disease caused by a bacterial toxin that affects your nervous system, leading to painful muscle contractions, particularly of your jaw and neck muscles. The bacterial toxin can get from the rusty steel to the wound.
Wound care to throughly irrigate the skin area with normal saline or hydroperoxide is needed. Cover the wound with sterile gauze. If the wound is deep, you need to get shots for tetanus