M8 what u need to do is take your whole phone apart(Look up on iFixIt) then maybe get a new battery(tenner down the phone repair shop) as loo water may have also affected the battery then leave it on charge for abt 25mins then change its screen(fiver down a repair shop. depends on if ur phone is an edge or normal). You just need to leave it on charge overnight after all that. Level 2 simple fix.