Sometimes it does it when i talk, it's the upper lip on the left side and sometimes around the chin area or bottom lip on the same side.
Keep worrying it could be the start of a muscle wasting disease as I know twitching can be that or worried i might have a tumour in my mouth or face that could be pressing on nerves and causing the twitching.
It's quite persistent and it just won't go away!! My mouth feels deformed.