This is probably caused by improper eating, or eating hard, biting or scratching the cat's breasts when breastfeeding after childbirth. My cat is like this, don't worry. This version is mastitis. Take some Li Shuang tablets and amoxicillin powder, and insist on spraying lysozyme. It will be better in about two weeks. Of course, different cats have different constitutions, so there will be different situations.