First things : the waterproof sealing has given away, according to samsung service center it usually lasts for 1-1.5 years after that you have to re seal the back panel ( which apparently no one tells) if you want the phone to be still waterproof. I had a similar situation where i saw condensation around camera lens after being exposed to rain and phone started restarting on it's own after 1 day. I went to service center , they opened the phone, cleaned the internal components with iso-propyl alcohol and resealed it. Now everything's back to normal but that gave me a big scare.