First, remove the hair surrounding the wound to provide a 1 inch border (minimum). The hair will interfere with treatment and serve to irritate the wound.
Then I would clean it with a dilute mix of betadine and take the dog to the Vet. Follow by placing a Cone of Shame on the dog, Elizabethan Collar. This will prevent additional irritation from chewing on the wound.
The dark are in the center is concerning. This does not appear to be a typical "hot spot" due to the center area.
FWIW, peroxide is not a good cleaning agent. Betadine is a better choice that is widely available in any drug store in 8 oz bottles. Betadine is useful for wound cleansing on animals and people. Hospitals use this to prep surgery sites.
Use good hygiene practice to clean the wound after the hair is removed and the Cone is on. Wash hands, clean gauze or cloth, mix Betadine with clean warm water, add Betadine to the water to obtain a dark tea color, clean the wound with dabbing, flushing, rinsing. Allow to air dry. Go to the Vet. You could probably do a walk-in for treatment.
Please follow up with the diagnosis and final treatment.