No sound (speakers/jack) + microphone's dead after spilling water
I repair Macs for a living, and have seen just about every possible WRONG way of handling a liquid spill.

the answer is water.

If you inject water into your mac, you've f'd it up.  

Consider 1 drop of water in a Mac to be the equivalent of ingesting 2 pints of JackDaniels in your body.

Drink 2 pints of Jack, and let us know how predictable you are... yeah.. it isn't going to end well..IF you end up with a hangover instead of an ER trip, you're lucky..

Water in your Mac is the same way. It is lethal.  as in, deadly. as in, if you do it, STOP everything and fix it. or your Mac could very well die.

General stupid ways of handling spilled water could include:


crossing your fingers and hoping that nothing got hurt
inserting your Mac into a gallon of rice and hoping that it dried out with no damage
inserting your Mac into a microwave to dry it out
restarting your mac (or plugging it in) without having disassembled it and cleaning out the water.
logging onto the internet with the mac and querying others to see what they'd do.


General intelligent ways of dealing with spilled water would include:


IMMEDIATELY shutting it off
NOT restarting it
NOT plugging it in
removing the battery (if removable)
fully disassembling the laptop (or taking it to a shop which does the above)


Water leads to all of the following actions:


shortouts (chips burning up)
corrosion
blown circuits
battery failure
fire
permanent damage
mold


IF you spill water in your Mac, shut it down. do not reboot it. remove the battery. disconnect power. Take it to a professional shop who repairs issues like this.

letting it simply sit for a few days will only prolong the damage, because water causes corrosion. 

The ONLY correct action after a liquid spill is to fully clean the boards, dehydrate them, then reassemble.  and if you don't know what you're doing, you're likely going to cause MORE damage.

Based on your explanation, your Mac got water in it. and your running of it has likely blown the ADC circuit on the logic board, or possibly part of the USB sub-circuit.