There's only 2 professional answers to this.
Clean with alcohol.
Take it to a technician for ultrasonic bath.
I joined this community just to tell you that you should not follow the advice of How to dry out a wet phone? suggested by Shadow Wizard.
Almost all of those answers are wrong and it is really sad that the question has been protected so I can't even put the correct answer.
NEVER NEVER NEVER use rice to dry out a phone. It's just a stupid myth. Anyone in the cellphone repair industry will shake their heads at this.
You want immediately turn off your phone and take your phone apart. Completely disassemble it. Dry it. Use a high grade alcohol that doesn't have a bunch of additives to clean out the impurities left by the water.
Water is not harmful to phones, the impurities in water are harmful to phones.
So what is rice going to do? NOTHING!!!!
So you have an iPhone? You're out of luck. They aren't built to ever be taken apart by anyone. Even apple technicians. So you can wait and hope for the best.
Which the best case scenario is that it will die in a couple years. Water damage doesn't always affect devices right away. It could take years for the affects to show up.
You can take it to a reliable local cellphone repair facility and maybe, MAYBE they might have an ultrasonic bath. However, a lot of cellphone repair places just see this as free money and don't actually repair the phone because it's not a reliable way to repair water damage. But it works sometimes
Did I mention to never use rice?
Now more specifically to you. It's in your screen. That's probably the worst place it could be because I don't even think any technician is going to suggest giving that an ultrasonic bath. You're in the worst possible situation you could be in.