Green pus coming out of a dog's tick wound is an indication of infection. When a tick bites a dog, it can introduce bacteria into the skin, leading to an infection. The bacteria multiply and produce pus, which is a mixture of white blood cells, bacteria, and dead tissue. The green color is due to a pigment called pyocyanin, which is produced by certain types of bacteria, such as Pseudomonas aeruginosa.
Pus is a sign of infection and should be addressed promptly to prevent further complications such as tissue damage, spreading infection, and fever. If you notice green pus coming out of your dog's tick bite wound, it's important to take your dog to a veterinarian for proper treatment, including antibiotics and wound care.