What are these red spots under my dog's mouth? Is it an infection?

From the photo, Puddin’s mouth does look red and I am suspicious of an infection or an allergic reaction. I recommend to protect the area from any trauma by having her wear an Elizabethan collar at all times. I also recommend to have her examined by the veterinarian to get this cleared up. I hope this helps and please feel free to post any additional questions.

This presentation could be due to a trauma or localized spot of skin infection (likely to be caused by bacteria). A check up, appropriate disinfection and possibly antibiotics (oral, topical or in a shampoo formulation) are needed to solve the problem. Disinfection may be started at home with very diluted hibiscrub or betadine or salted water baths. Buster collar may be useful as well to avoid any scratching (if any). Hope this answer was helpful, but 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 this answer was helpful please let us know, this will be used to improve our service!

This doesn't look like a hot spot to me, it looks more like a skin infection. It needs to be diagnosed in order for it to be treated correctly, so I would take Remy into a vet in the morning to have this checked out. Best of luck.

This looks like a skin infection, you will need to take him to the vet ASAP, the fur in that area will need to be shaved and he will need to get a course of antibiotics in order to have this treated.

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. There is no way of knowing what it is just based on its appearance. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have him evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!

This presentation could be due to a trauma or localized spot of skin infection (likely to be caused by bacteria). A check up, appropriate disinfection and possibly antibiotics (oral, topical or in a shampoo formulation) are needed to solve the problem. Disinfection may be started at home with very diluted hibiscrub or betadine or salted water baths. Buster collar may be useful as well to avoid any scratching. Hope this answer was helpful, but 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 this answer was helpful please let us know, this will be used to improve our service!

That appears to be a bacterial infection of the hair follicle around the mouth. Moisture around the mouth from eating and drinking can contribute. You could try a topical antibacterial wipe ( like an acne pad) after meals for the next few days. If that doesn't help you may need to see a veterinarian for oral antibiotics or other medications.