Help! Water under the skin, delamination and damage.

well you ain,t going to like this, if your going to fix it, you need to open it up. theres most likley lot of rot in there. so, find a repair shop who does this work. or jump in and do it. sorry some body sold you a spung. 40years back I did one , lot work. but like new when I rolled down the road. maybe the guy will take it back. yet its got lot years on it.