Hi there and thank you for using pet coach to address your concern. From the pictures it appears as though chewy has a lot of inflammation in this area. I would suspect he has been chewing and licking this area and has caused a hotspot (moist dermatitis). I would recommend placing a rigid plastic cone around the neck to prevent him from licking this area. I would also recommend applying s topical medication such as zymox topical ointment and apply to the area until resolved. You can find this ointment easily online. If the area does not heal or worsens, I would recommend having a veterinarian take a look at this for further testing and treatment recommendations. I hope this helps guide you in the right direction.