My phone comes on but I cant open it

Hi

The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the phone's operating design and could damage the components. The corrosion starts immediately and continues until it is properly cleaned away

First do not try to charge or to turn on your phone and then remove the battery as soon as possible to minimize any further damage.

Then you need to dis-assemble the rest of the phone and clean all the affected parts using Isopropyl Alcohol 99%+ (available from electronics parts stores) to remove all traces of corrosion and water. If possible do not use "rubbing alcohol" as in some cases this is <70% IPA, can contain additives and is not as effective. If you do have to use it, check the label to verify the amount of IPA. The higher the percentage of IPA the better

Here is a link that describes the process. Electronics Water Damage

As always with electronics, especially surface mounted pcb, be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the boards. Remove any shields that may be covering some components as the water may have got in under them and corrosion is occurring there also.

Hopefully after you have done all this the phone might possibly work correctly again.

Here is a link to the ifixit Samsung Galaxy A50 guides which may be of some help.

If this process seems too daunting, take your phone to a reputable, professional mobile phone repair service, experienced in water damage repair and ask for a quote for a repair.

If you decide to do this, do it sooner than later. It isn’t going to fix itself