MOBILE PHONE NOT DETECTING MEMORY CARD

First of don't post in all CAPS. It amounts to SHOUTING in Internet Parlance.
And regarding your problem take it to a repair person.

Memory cards can get wet: there are no parts that absorb water or melt. However, if the user attempts to use the card when it was wet, it could be damaged by a short circuit (esp if it was salt water).

The phone, too, has few components (other than the water detection sensor) that are affected by water, however water can create short circuits that destroy components if the user attempts to operate it when wet, it will cause damage. Water (especially salt water) will cause corrosion for certain internal parts (e.g. connectors, switches, ribbon cables) that typically will render the device useless.

Note that I used BOTH UPPER and lower case letters....