Nerve blocks to fill lips with filler?

Typically, lidocaine or some other anesthetic is used for a nerve block to make injections to the lips more tolerable. The nerve block itself wears off in a maximum of 2 to 3 hours although some bruising can occur and increased swelling if a large amount was used. If you received botox in the adjacent area that may very well be the source of your asymmetry or weakness of the facial muscle. Other than that sometimes filler may be placed too high or too low and this can cause the asymmetry. However, the nerve block effects should be gone shortly after the procedure except for perhaps some bruising and swelling.

I typically do not use nerve blocks as they change the shape of the lips and make injections much less precise and difficult -- but this is personal preference.  I suggest getting filler performed with a cannula next time without a nerve block so you do not get complications like this.  If you are concerned of the look, please have the area reversed with an hyaluronidase injection.  Best, Dr. Emer.

I'd say that most injectors will use local anesthetic injected into the lips near the gum line to numb them before lip injections.  The lips are very sensitive and this can make the procedure quite comfortable after the initial numbing injections.  Having said that, one of the newer techniques involves usage of blunt tip cannulas instead of cutting needles to perform the injection.  The blunt tip cannula slides through the tissue rather than cutting through it and is thus less traumatic and painful (and less bruising).  Depending on the patient, I sometimes do not use local injections with this technique.  The asymmetry in your smile was likely due to the local anesthetic.  It will numb the sensory nerves as well as motor nerves.  If there is any asymmetry in the local injections from one side to the other, then yes, this can happen.  As you have experienced, this should be temporary (lasting an hour or so depending on the type of local used).  All the best!