Consequences can be different depending on your dog's age (young and older dogs are more sensitive), size, health and where they have been bitten (bites on the muzzle are the worst). The venom contains enzymes that cause a strong local reaction: the area around the bite (that is where you can see, if the hair is not to thick, two small punctures just a few millimetres apart) and the wider area around that will appear swollen, hard, warm, painful, reddened and ooze serum and blood, and will be at its worst for an hour and may persist for a few days. A few minutes after the bite, symptoms may include weakness, difficulty to stand, shortness of breath, palpitations, cyanosis and, more rarely, muscular spasms, hypersalivation and convulsions. These symptoms are caused by the toxins in the venom, which in rare fulminating cases can provoke disseminated intravascular coagulation with possible shock, coma and death. With dogs, acting on the affected area to remove the venom for example, sucking it in with a syringe or performing a local incision are almost always impossible, so the only think you can do is slow down the venom absorption process while you go to the nearest vet. One way of doing this is using a tourniquet or applying an elastic bandage, but only if the dog has been bitten on a leg or tail, and it's often ineffective, because usually dogs get very agitated and the tourniquet can move or come undone. The only effective way is cryotherapy, spraying cold gas and applying ice or dry ice on the affected area. If possible, it is important to disinfect the area with non-alcoholic solutions, to prevent infections that, however, are almost unavoidable and will need to be cured with antibiotics.