1. Vaccine adjuvant components are not well absorbed, resulting in small bags under the skin.
2. When the vaccine is injected into the skin, the drug will swell after absorption.
3. Due to the cat's own constitution, it may swell up because it does not absorb the vaccine ingredients well.
4. After vaccination, the affected part of the cat appears bulging, which may be caused by the cat scratching itself.
5. After the cat is vaccinated, the bulge may be caused by local infection or allergy.
If the bulge is getting bigger and bigger, or even broken, please take the cat to the pet hospital in time.