Thank you for contacting us. There are many causes of swelling in pets. It may be an allergic reaction, or it may be due to an external wound, or others. It is important to determine the exact cause, as treatment differs depending on the cause. If an allergic reaction is a problem, take an antihistamine and the swelling will go down. If it is caused by an external wound, observe whether there are any wounds or traces. If external wounds are visible, disinfect and bandage the wounded area. If you do not see any of the above symptoms, it is most likely a medical condition. For the time being, apply ice packs to the swollen area. If the swelling does not go down by tomorrow, an appointment with a veterinarian is absolutely necessary for a differential diagnosis to determine the cause.
If you have any additional questions, please come back to us! Thank you.

the picture is a few weeks ago and the video is today showing the torso swelling

he had a swollen midsection and yelps when he walks or is petted