That’s probably why it’s still turning on, but some water must have got under the screen somehow.
I would take it to Apple when they re-open(should be 15th like other shops?) then they will tell you exactly what’s wrong with it and how much to get it fixed, then you can make your mind up if it’s worth fixing.
You might be able to get it fixed cheaper elsewhere, but then the parts used may not be genuine Apple parts. I’ve heard of people getting screens fixed on the cheap from “the guy on the market”, then the screen never works as well as it did before, or the colours on the screen are inferior.
For now I’d turn off the phone until you take it in for repair