Do The Contraceptive Implant And IBS Affect From Shedding Body Weight?

Hi I m thinking about buying the slide in because I am a size 16 wanting to be an 8-10 but I was wondering if the contraceptive implant will affect them Atall? Like cause a reaction? I also have ibs and they can give stomach pain so should I be worried? Also do they even work...and with loosing weight that fast how can I stop loose skin? Last thing is are they harmful? Because some people have had nose bleeds etc from them...or is this just an allergic reaction? Sorry about all the questions I just want to be sure before I spend £100 on pills :)