First, control ur diet, high salt intake can lead to cell to take in more water. So it will makes u look loose and swelling. If u feel low salt diet would make u take less electrolyte, try to take some fruits as snack. And don't eat junk food. Make sure your dieting is regular and breakfast is necessary every day.
Second, exercise is the lever. U should know the right way to do. No need to worry about muscle growth. Because u r a gal, which means lots of estrogen inside u that inhibits muscle growth. But sometimes a bit muscle will makes more slim, healthy, and beautiful. For overall exercise u can take jogging. Remember, low intensity, which means u r running, faster than strolling. And long time, can not stop and resume later, 30 minutes once, three times a week is ok for beginner. U can increase the time gradually when u r adapt for this phase. Because I do not know how energetic u r. For local exercise, there r some terminology that is hard for me to explain to u. Ok, just two simple ones, 1.bicep curl; 2. tricep extension. Same principle with jogging. Ok, i try my best to explain how to do them, if u really don't know, ask ur friens who know about them. I am sorry for that. 1. bicep curl, sit or stand with ur arm pendent, take a light weight(eg, the textbook u do not want to take to study room every time), keep ur upper arm stable and besides ur trunk, just move up ur forearm with the weight, then let it down slowly with control, that's all. usually, 18-20 times a set, 3 or 4 sets, depends on u. 2. tricep extension, lift up ur arm beside ur head, looks like u r the smartest gal in the class, keep ur upper still, lower down the weight in ur hand by ur forearm only, then lift it up also keep ur upper arm stable. U can do them single arm or double or alternately, up to u. At the beginning, u may feel it tough, u arm may be a bit painful, that's normal due to muscle degenerative for lack of exercise, kind of retrogress. What I have told u to do, it's to burn fat. During the exercise, u body will break down muscle first and then burn fat. So that's the reason why we need long time. and due to the light weight u r using, it will not leads to inordinate muscle growth. That's what we call it low intensity in the principle. But not too light, at least u can feel about it.
Ok, that's what I can take out, sorry for the curtness. Keep fit.