Bruising around the wound after a dog bite is usually caused by subcutaneous bruising, and the wound needs to be cleaned and disinfected in a timely manner and inoculated with rabies vaccine and rabies passive immunization preparations. Bruising around the wound after being bitten by a dog is usually caused by bleeding due to rupture of subcutaneous blood vessels and blood pooling under the skin, which is classified as class III exposure. The wound should first be thoroughly irrigated under running water for at least 15 minutes, after which it should be disinfected using iodophor or alcohol. Once the wound has been treated, a visit to a vaccination center should be made within 24 hours to complete the rabies vaccine and rabies passive immunization preparations. The bruising around the wound usually disappears on its own as the wound gradually heals and the bruising is gradually absorbed.