What happens when an iPhone gets wet?

I have had my iphone for a little over 6 months about two weeks ago a cup of water fell on y phone, I was out of the room so I don't know how much water there was… I dried it off with my blanket and made sure it was ok… It was working fine for a about a minute or so but then the keyboard shorted and kept typing random letters, I looked online what to do and I turned the phone off and put it in a baggy of rice, it was in there for like thirty minutes and I took it out to check on it, it was back to normal! I left it in the bag over night and used it the next day, it's been running slower and sometimes I have to touch twice to get an app going, sometimes it exits out of an app by itself too! Is this an effect of water damage or just a normal iPhone?

Normal iphones do this sometimes its annoying although this could be water damage.hard to say:\