A big bump on a dog's neck may be caused by a recent injection, mosquito bites, external parasites, or tumors. It needs to be judged based on the dog's own condition. If it is just after the injection, it will usually disappear in 1 to 3 days; if it is a mosquito bite, you need to apply anti-inflammatory drugs; if it is not caused by external factors, it is best to take the dog to the pet hospital for examination to confirm the cause and then treat it. Sexual treatment to avoid delaying the condition.