Take the dog to the veterinarian immediately for examination and diagnosis. Only the veterinarian can determine the exact cause and provide the correct treatment. While waiting for medical treatment, warm water and an appropriate amount of non-irritating detergent can be used to clean the dog locally. Gently wipe the testicles area with a soft cloth to remove any dirt or secretion.

Avoid dogs licking the testicles area to prevent further spread of infection. Please follow the veterinarian's advice for treatment. This may include oral antibiotics, topical ointments, or surgery, etc.

During the dog's recovery, the dog's living environment should be kept clean and hygienic, and mattresses and cleaning equipment should be replaced regularly. Please remember that the above suggestions are for reference only, please consult your veterinarian as soon as possible for professional advice and treatment options.