it does differ from one person to another. but if your skin is bad then you may want to consider dianette which takes about 5 months to take effect but then many women have problems with it as they put on weight.
theres no miricle pill that will both improve skin and help weight but its a matter of trial and error tbh, its hard to pinpoint what will work for you. but many pill increase your appitite not actual weight, so maybe watching what you eat may help. but overall dianette or yasmine are considered best for skin.