To me this looks like tissue with pathological changes and you really need to see a vet as soon as possible.
The entire gums of upper and lower jaw look swollen. At first glance I thought this was a puppy with milk teeth because only the upper half of the teeth is visible above he swelling. The "second" gums look like an ulcer - a mutation of tissue that needs to be treated.
Dogs are predators and in the wild predators survive only as long as they're strong and healthy. That's why most dogs don't show pain and discomfort that is tolerable to them. But this tissue looks at least sensitive...
Please note that I am not a vet or even a doctor, but I work in the production of medical devices and gained some medical knowledge in my line of work. The red dots you see are a possible indicator of dysplasia, a pathological mutation of tissue that can develop into neoplasia (better known as cancer) if untreated.
These terms are related since they represent three stages in the progression of many malignant tumors of the epithelium. The likelihood of the development to cancer is related to the degree of dysplasia.
- Dysplasia is the earliest form of precancerous lesion which pathologists can recognize in a pap smear or in a biopsy. Dysplasia can be low grade or high grade. The risk of low-grade dysplasia transforming into high-grade dysplasia, and eventually cancer, is low. Treatment is usually straightforward. High-grade dysplasia represents a more advanced progression towards malignant transformation.
- Carcinoma in situ, meaning "cancer in place", represents the transformation of a neoplastic lesion to one in which cells undergo essentially no maturation, thus may be considered cancer-like. In this state, epithelial cells have lost their tissue identity and have reverted to a primitive cell form that grows rapidly and with abnormal regulation for the tissue type. However, this form of cancer remains localized, and has not invaded past the basement membrane into tissues below the surface.
- Invasive carcinoma is the final step in this sequence. It is a cancer which has invaded beyond the basement membrane and has potential to spread to other parts of the body. Invasive carcinoma can usually be treated, but not always successfully. However, if it is left untreated, it is almost always fatal.
That's why it's easy to say "it's cancer" at a glance, but what stage of cancer has to be determined in a laboratory.
As far as I understand it, the cause of dysplasia is constant stress on a cellular level. Some cells grow bigger than normal, some have a much bigger nucleus, others divide too early. All this can be examined in a histological examination.
Image source: Wikipedia
Since the blood vessels are stressed as well, they grow longer and thicker and become visible in a "punctuation" or "mosaic" pattern.
Image source: Journal Of Oral & Maxillofacial Pathology
As to what causes this cellular stress, I honestly don't know. I do know that it can be caused by certain viruses or constant injury (like biting the same spot of your tongue over and over again). I assume that an allergy might cause this kind of stress, but I honestly don't know for sure.
Please ask your vet for the probable cause and a treatment plan. Maybe a treatment with antibiotics or other medication can help. Maybe a different brand of food and using stainless steel bowls for water and food can help if it's caused by an allergy. There are some cases where pets react allergic to plastic bowls.
If you treat the cause of the dysplasia, your dog can live without major problems for many years. If the cause cannot be treated, chances are high the pre-existing dysplasia gets worse and develops into malignant cancer.