My dog's genitals are purple with a closed wound. Is it infected?

This could be skin irritation/infection but it could also be subcutaneous bleeding (which can be serious). I strongly suggest you have him examined by a vet. In the meantime you can try these medicated pads on the affected areas in case of infection. ( https://www.chewy.com/douxo-chlorhexidine-3-ps-pads-dogs/dp/110823 )

This presentation could be due to a trauma and localized secondary skin infection (likely to be caused by bacteria). A check up, appropriate disinfection and antibiotics (oral, topical or in a shampoo formulation) are needed to solve the problem. Buster collar may be useful as well to avoid any licking/scratching. An immediate check up at your local veterinarian is needed. Please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.

If the cut is small and looks as if it can heal on its own you can try cleaning it with a dilute iodine solution 1-2 times a day. You can also apply a small amount of triple antibiotic ointment on the area. It is important to make sure he is not lickin the area, as this can delay healing and make infection worse. If the cut is any larger than 1-2 centimeters then I would recommend having it looked at by a vet because it may have trouble healing. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach. Best of luck!

Thanks for using Petco Pet Education Center, formerly Petcoach! It really appears to be healing well on its own though it is hard to tell. If it continues to heal, it may not need any therapy at all. If at any point it starts bleeding or releasing a discharge or becomes bloody or painful, have him evaluated by your veterinarian at that point for further assessment. Otherwise, this is possibly going to heal on its own. Good luck and have a great day!

Unfortunately it is hard to tell when we cannot see exactly where on the penis this purple spot is. If it is a round swollen area, then that would be the bulbus which swells during copulation and locks the penis in the vagina of the female. If people separate the two dogs rather than wait until they part themselves, this bulbus can get injured and the female can also get injured. It is not a good idea to let this male mate with the three females in heat as he will introduce bacteria into their vagina and possibly uterus and so could cause a uterine infection (pyometra). If you could take some good photos of your dog's penis, we could better assess the situation and give you a more specific answer.

Ouch! Poor Dylan! This looks like a little local infection that he has been licking. I would place an e-collar I him to prevent licking. You can clean it with mild soap and water. And I would also put some neosporin on it twice a day. If it is not improving in the next day or two then I would definitely take him in to see your veterinarian for an exam. Your vet will be able to prescribe some oral anabiotics and some stronger topical medicine if needed. If at any point he is not eating or is lethargic then I would also take him to your vet. I hope this helps!

This looks like a local abscess from a bite wound or an insect bite or if there is a mass there it could have been a cyst that got infected. If he is licking it, I recommend to place a cone collar to prevent him from doing that. Also I would clean it with a mild anti-bacterial soap and water. You can try putting some neosporin on it but if it isn't improving, you will likely need to see your vet for an exam and some oral antibiotics to get rid of the infection. I hope this helps.