Generally speaking, with any liquid spill on a laptop, I’ll remove the battery immediately. Next, I disassemble the unit to see were the liquid made it to, and rinse those parts with alcohol, and let it dry thoroughly before reassembly and testing.
If it was powered on when the spill happened, you may well be out of luck and need a new laptop, depending on the damage, as a repair could be more than a new one (depending on age, parts availability, etc…). It largely depends on what the water (since it will conduct electricity) covered inside, and possibly shorted out. It also depends on the mineral content of the water as to how conductive it is - tap water is usually much worse than some bottled waters.
If there was water that hadn’t dried yet when you attempted to turn it on, that may have made matters worse - again, dependent on where the water was. Spillage into a laptop is never a good thing.
Laptops can be notoriously difficult to get apart, so you might see some very minor scaring along the edges of the upper and lower shell, depending on the skill level of the technician and the tools he/she used. Operationally, IF it is able to be cleaned and restored to operation, should look identical prior to the spill as far as the display, etc… goes.
I’m sorry I can’t give you any well defined answers, or at least answer you want to hear. Based on my limited knowledge of your exact situation, the above is the best I can do.