The main problem with storing cars is humidity, especially under covers, once the cold air condences there is nowhere for it to go so it just sits there and soaks all aspects of the car, then it sits there causing all sorts of issues such as the ones that you are now experiencing such as mould and micro blisters, it seems a short time to have had such an adverse effect on your paintwork so I would imagine that something was amiss with it to begin with but I'm afraid the blisters will more then likely be down to bare metal and will need to be fully stripped before repainting,
My Z is currently stored in a large workshop and therefore doesn't undergo the problems with hot and cold air, however once its at home it will be in a small garage, it shocked me how wet my last Z got whilst in this garage due to condensation,in winter before I left for work every morning I would open the garage doors to let theair circulate and dry it out
My Z is currently stored in a large workshop and therefore doesn't undergo the problems with hot and cold air, however once its at home it will be in a small garage, it shocked me how wet my last Z got whilst in this garage due to condensation,in winter before I left for work every morning I would open the garage doors to let theair circulate and dry it out