Bloat is very serious. Is this more gas or a severe and hard distension of the abdomen? A product like simethicone can help with mild gas.
What is their diet? How did this come on? Do they show any other signs of illness? Diarrhea?
- And got the T-shirt
If I were you, I'd see if I could find an exotic vet who knows how to treat guinea pigs. This one does not.
And vegetables are fine for guinea pigs.