Should i take a water pill, after taking prednisone, for asthma flaring up, because its making me fat and puffy lookin, even though i already pee alot?

No: Prednisone often increases one's appetite and steers the body towards producing more fat. Although some may retain sodium (thus water) because of prednisone, this is not a major cause for your weight gain. Most people with asthma do not need Prednisone as a controller drug today. Suggest you consult an allergist. After you can get off of prednisone, you'll have a better chance to lose the weight.