As far as I was concerned my iPhone 6s Plus was dead after a swim session in the beach and my waterproof cover was compromised. After 3 days in rice didn't work I took it to the nicest shop owner that went out of her way and drove to work for just for me. She opened up my phone and and worked her magic like a nuerosurgeon only more personable and cheerful. Half an hour later I was good to go and for a very reasonable fee especially considering we're in a touristy area even though I was there on business.
Don't give up on your phone until you see the nicest and most knowledgeable phone wizard Yuxemy!