What is Dry up ?
Dry up is (verb) 1. to stop flowing The heat wave has made the rivers dry up. The government grants have dried up and it looks as though the theatre will have to close. 2. to stop talking, because you can’t remember what you were going to say He dried up in the middle of his speech, and sat down hurriedly. As soon as she got on the stage she dried up.
source: Easier English, Student Dictionary Upper Intermediate Level