In general, there are no special and complex preoperative preparations except the initial consultation and a few tests to confirm that you fulfill the selection criteria. This will include a general assessment of your face and neck, and check the severity of sagging and related conditions. Besides, some laboratory tests will be done to rule out any bleeding disorder that can alter the results.
Apart from these, you need to have realistic expectations from the treatment. So, if you have any queries regarding the process and results, you should ask them your doctor beforehand.