 [ Symptoms ] we are traveling my son has diarrhea and losing weight on anti malaria pills [ Disease ] aside from the skin issue which i will get to in a moment you are probably not drinking enough water most adults should aim for 8 glasses a day though that is just a number someone picked out of thin air clearly if you are just taking a few sips of water with your meds you are probably not getting enough water now about that skin if you are talking about that flabby skin on the backbottom of your upper arms i am afraid i do not have good news many women develop that loose skin and there is nothing you can do short of surgery to get rid of it even exercising the triceps muscles will not reduce this excessive skin many women are prone to developing that excess skin by middle age it may be caused by having gained and lost weight over the years and who among us women has not gained and lost weight from time to time over our lives so i am sorry i can not tell you the flabby arms are due to dehydration that said i suggest you drink more water it is good for your overall well being wishing you all the best