Vegetables must be given daily. Lettuces like endive, romaine, radicchio, etc. are all good every day foods, but not iceberg lettuce. Cherry tomatoes, chard, 1 baby carrot, parsley, cilantro and peppers can also be given daily. When your baby pig reaches the age of 6 months, parsley should only be given every 2-4 days.
Cabbage, celery (chopped up into small pieces) and celery leaves, various fruits, and cucumber can be given every 2-4 days.
What hay and dry food are you feeding your little piggy?
As for the water issue: some pigs don't drink very much water at all. My pigs drink very little - maybe 20ml a day, sometimes a bit more, sometimes a bit less. If you don't see your pig drink at all during the next few days, I would offer watery veggies (including cucumber) maybe once every 2 days. Have you tried a water bowl, instead of bottle?