Hi Matthew and welcome to the community Forum!
Did you read the “water wiki”?
There’s a lot of good advice about rain and other water damage, have a look round. For instance, this longish read with a happy ending (solution : patience, mostly - we’re talking days).
You might want to open up the phone to improve ambient air circulation and to check whether the liquid contact indicators have turned red (if not, white dots). You can use a fan or hairdryer but NO HEAT, just ambient temperature.
NO RICE! Rice is for puddings or curries.
See also general advice such as Electronics Water Damage - iFixit