Urgent: Street Dog with Open Wound on Front Right Leg

Details

A friendly street dog has an open wound on his front right leg, possibly caused by a bike accident. The wound has been opening repeatedly for the last 4 days, and the flesh is visible. He keeps licking the wound and spends nights in a muddy area with other street dogs. He trusts me, but I cannot safely touch or examine the wound. I am not his owner and cannot afford paid treatment. Please help with free rescue, wound assessment and treatment if possible.