At this point I can give you some basic guidelines for this lesion but if it is not improving or growing I would advise a veterinary exam.
1.) No licking! Glad you have purchased an e-collar to allow healing because licking introduces oral bacteria to the area and can increase risk of inflammation and infection
2.) Trim the hair around the wound
3.) Use ivory soap and water or dog oatmeal shampoo to the area twice daily with ten minute contact time before rinsing and tap dry. Please minimize hydrogen peroxide which has been proven to delay wound healing versus promote it
4.) I prefer to not apply salves or ointments because it traps in moisture to the area and reduces healing or delays healing time. If needed you can put a very thin layer of a triple antibiotic on the area after cleaning
5.) Remove any scabbing that occurs with healing. Again it also traps in moisture and then can actually abscess
6.) Benadryl 1 mg/ pound every 8-12 hours as needed for itch but may cause mild sedation.
7.) Photograph the lesion with a ruler next to it so you can monitor its size and shape weekly
This can be due to a contact allergy, infection, bug bite, ringworm, immune mediated to name a few but the above should help quiet it down and hopefully provide relief to allow healing
Please let me know if this information makes sense and any additional questions i can assist with or clarify today.
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