Q: iPhone water damage slow to appear - more then 24 hours

I Dropped my iphone 6+ in pool yesterday- immediately dried it - there was no noticable damage- phone worked fine rest of day never noticed a problem, charged it fine that evening (not thinking there was any issue with the phone). Worked fine all day (used it all day) went to charge it tonight because battery dead - Won't Charge, can't reset either!!! Now wondering if water damage.  Would it take this long to show damage without phone acting strange all day.??  Any suggestions?