Can the furnace pressure switch be damaged due to water
If the switch was in the water, then yes. The water will create a short between terminals, or corrode them. You can test the switch to see if it still functions. Turn power off to the furnace, disconnect the tube to the switch, and gently blow and or suck. Listen for a click sound. That would indicate is the switch will latch. Next would be to test with a multimeter. Continuity to ground, and continuity terminal to terminal while blowing or sucking to activate the switch.