Will my stretch marks/extra skin go away!?! PLEASE HELP!!?

alright im 19 and i gained literally like 50 pounds in only a couple months and it resulted in me having hideous huge stretch marks all over my stomach and the insides of my arms. now i got my life back together and im starting to lose weight again. as my body and skin shrink back to normal will the stretch marks go away? will my skin even stretch back to normal or will i have excess skin floppin around? im 5'6 and i weight 200 now and my norm healthy weight is 150. what do you tink? is there anything i can do to try and tighten my skin as i lose the weight?