What Causes Swelling Of Veins Inside Mouth?

My cat was diagnosed with lymphoplasmacytic colitis on 2/6/15. she was put on C-Budesonide 1mg . today I noticed that she hasn t gone pee or poop since 6:30 am, maybe longer, approximately 16 hours that I am aware of. She has also licked all the hair off her lower abdomen and I see dried blood on her anus. She has eaten, but not drank in those 16 hours.