Yes, using your normal sleeping medication will not have any effect on your filler or vice versa. The swelling from the injection is likely causing your pain, which will go down after about two weeks. You may want to ice the injection site to help reduce the swelling and subdue the pain.
Hello - it is totally fine to take some medication to help you sleep. Just be careful that you don't end up sleeping on your face, and to try to keep your head elevated with at least 2 pillows. This will help keep swelling from building up in the lip area while you sleep. Enjoy your injections! Best - Dr. Singleton