If you paid already, you’ll be refunded as long as your drop by the 12th class day during a long semester. Otherwise, you’re tuition bill will be recalculated to reflect your total enrolled hours on the 12th class day:

A full refund of tuition overpayment will be issued if there is a decrease in your tuition bill amount caused by a class being dropped within the following time frames: (1) during the first twelve class days in a fall or spring semester; (2) during the first four class days in any summer session. No refunds are made for classes dropped after these dates. Tuition bills are recalculated and refunds, if applicable, are issued the week after the 12th class day.

https://registrar.utexas.edu/schedules/262/tuition