Some female cats are allergic to surgical threads, and there will be a small amount of fluid accumulation in the skin during healing, which will cause a hard lump to bulge under the wound after the female cat is sterilized; in addition, the fat in the female cat’s body has been pushed due to the surgery. Squeezing can also cause bulging. The owner can wait until the swelling of the wound subsides to see if there is any change. In addition, the wound condition after sterilization is not the same for all cats. You can ask the surgeon who sterilized the cat for specific reasons.