I dropped my Samsung galaxy s7 in water. It was submerged for less than 10 seconds, I turned it off within 30-60 seconds after that. It was working properly when I pulled it out of the water and while I was wiping it's surface dry, and I also managed to shut it down cleanly. I've wiped the audio jack opening and the USB port with a thin piece of tissue paper and also dried out any openings with a hair dryer. On hindsight probably shouldn't have done that, but it's already done. I've pulled out the sim card, and at least the sim card slot looked completely dry inside. It's since been turned off and is completely covered by dry rice.
How much damage am I looking at? This is the first time I have had water problems with a phone with an unremovable battery, and it doesn't look like I can do much else with it at home. Should I take it to a repair shop anyway and have it opened and dried? I don't know how much it would cost, and since it is an old phone anyway I don't know if it'll be worth it if they ask too much. Since the phone seems to be pretty water resistant I am wondering if I can just brush this off.
How much damage can I expect? If the phone turns on, charges and works normally is it safe to continue using it as usual? I am okay with keeping it under rice for 24 hours or more if that's necessary. When is the earliest I can turn it on again?