Dark rash on my dog's head: Is it a hot spot or something serious?

I looks like a hot spot. I suggest you use apply hydrocortisone spray or hydrocortisone cream to the affected area 2 times per day. If after a week or so it is not looking better then he should see your vet. ( https://www.petcoach.co/dog/condition/hot-spots/ )

It could be a hot spot (moist dermatitis) or an injury of some sort. It is difficult to determine where on Caesar it is located from the image provided. You have two options. The first is to have him examined by your veterinarian. The area may need to be shaved to provide a better look at it. Afterwards, your vet can diagnose it and administer the appropriate treatment. This could be antibiotics and anti-inflammatory medications if it is a hot spot. The second option is to monitor it at home. Use an e-collar (cone) if he is licking or chewing at it. Keep it as clean and dry as possible. You can use a plain, unscented baby wipe or a pet wipe to gently clean it. If it doesn't resolve or causes discomfort, then Caesar will need to got to the vet. Monitor for rapid change or growth, discharge, bleeding, lethargy or pain associated with the site. These are symptoms that should be addressed by your veterinarian.

That looks more like a really inflamed “hot spot” to me. Put an ecollar on him so he can’t lick at it, and take him to your vet. He may need oral antibiotics and a prescription topical treatment. If you are unable to get him to a vet, use the ecollar as I mentioned, and try this product:https://www.petco.com/shop/en/petcostore/product/zymox-hydrocortison-cream Thanks for asking PetCoach!

This looks like an area that was scraped and now has a secondary bacterial infection. Please clean the area with a warm wet cloth and once rinsed and dried apply a thin film of antibacterial ointment on it. By washing it you should remove the dried up crusty skin. It may look more irritated but having it clean and open to the air it should heal more quickly. The rest of the skin looks fine. It may take several weeks or more to have the fur fill in. If you see more areas like this then an exam and skin scraping to determine the cause is in order. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Stella.

I really cannot tell what is going on in the photo. You can try using this spray on her 3-4 times per day. If after treating her for about a week and there is no to minimal improvement then she should see a vet. https://www.allivet.com/p-2842-vetericyn-vf-plus-wound-skin-care-hydrogel-spray.aspx

It looks like Tank could have what we call a "hot spot" or a superficial pyoderma (bacterial infection of the skin). You can read more about this issue at https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952981 . I would recommend bringing him in to see the vet. We often need to shave these areas and clean them with an antiseptic cleaner. Then sometimes an oral antibiotic/steroid is needed, others times a topical spray such as Gentocin spray is prescribed. I would be careful having him outside with this wound as it can attract flies/maggots which you don't want to deal with! I would recommend keeping him primarily indoors until the lesion is healed.

I'm not 100% sure what this spot is from just by looking at a photo. It could be just an injury but it could also be ringworm or skin mites (mange) or the start of a hot spot. I suggest you try this hot spot spray gel, 3-4 times per day. If after about a week or so you don't noticed much improvement or he starts to get spots in other areas then he needs to see a vet. https://www.petco.com/shop/en/petcostore/product/vetericyn-plus-hot-spot-antimicrobial-gel-for-dogs