I drop my keys in the sewage and now my alarm keeps going off and my back rear doors keeps opening how do i stop it before it drains my battery

your problem is likely due to liquid shorting the buttons inside your car's key. short term solution is to open the key and remove the coin cell battery from it. Usually there's either a screw or it pry's apart. After removing the battery the remote unit will need to be thoroughly cleaned and dried. I'd recommend trying to rinse it with rubbing alcohol and then putting it in a bag of rice for a day, enlisting the help of a technical friend, or taking it to the dealership/repair shop. In the meantime you should be able to use the rest of the key to operate your car without the remote function.