Phone has water damage, can I fix this on my own?

I was using my s5 in the hot tub. This was never a problem before. The phone dropped out of the hot tub and I put it right back in not realizing that the back seal had broken slightly. Ever since it has been freezing up and working very slowly. It thinks I am holding down the buttons when I am only pressing them once. Every time I press the home button it goes to the search page and I cannot get off of that page unless I continually press the back button or take out the battery. It is still usable, but very inconvenient. I have insurance through my carrier, but it will be close to $200 to have it repaired. That is as much as I paid for it brand new. I am wondering if there is a way for me to repair it on my own.