Look at this situation, it is obviously a cyst, which is caused by improper feeding. Dutch pigs are herbivorous rodents, and their intestines and stomach maintain peristalsis and digestion by eating grass.
So its food is mainly dry ladder grass+water. Occasionally feed some cherry tomatoes, sweet peppers to supplement VC, don't feed anything else, try not to. Even if it's okay for the time being, it will still cause harm to the body.
Never feed rice, potatoes, corn, other kinds of melons and fruits, cooked food and the like.