I'm taking hydroxyzine and prednisone for my sever poison ivy. weight gain help 10 points?

i decided to stop takng the prednisone because it has made me gain weight alot. (7 lbs in 4 days) and i have a chubby face still. im going to start forcing myself to drink a bunch of water to help lose the weight. Ive been also taking 50mg of hydroxyzine a day. will that typically make a person gain or lose weight? please tell me. thank you. how long do you think it will take me to lose the 7 lbs i did off this medication (prednisone)?