Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
How long has he had these signs?
Is he actually vomiting or have any diarrhea?
Is he drinking for you?
Is the swelling hard, firm, or have any discharge?
Are his gums pink or pale/white? Moist or sticky?
If you press on his belly, does he have any discomfort, tenderness, or tensing?
Could he have eaten something he should not have (ie bones, toys, plants, chemicals, etc)?