The weird faces are called secondary behaviors. They're a form of avoidance or escape behaviors. Meaning they're things that your body has learned to do to either avoid the stuttering moment or get out of it (escape). There are some good suggestions here to begin by noticing the behavior that you want to change and working with an SLP who is experienced in working with stuttering. The next step is to consciously work on not making the weird faces when you feel a stutter coming on. If the behavior has been used to help you avoid or escape stutters, when you don't do that behavior anymore, you're likely going to have a bigger, uglier, more noticeable stutter initially. Think about it like a nose job. When someone first gets a nose job, it's gonna look bruised and ugly for awhile before it starts to look better. Of course it's not so simple, because having bigger, uglier, longer stutters brings up more fear, anxiety, and feelings of self-consciousness. Also the more self-conscious you are of making weird faces the more anxious and nervous you will be and the more likely you will be to make the weird face. When you are able to reduce your anxiety and worry and self consciousness, it will be easier for you to change this undesirable behavior. One thing I can suggest that may be a good place to start is to begin shifting your thinking about the bigger, longer stutters that are likely to surface when you consciously stop making the weird faces. Tell yourself something along the lines of, "When I have bigger stutters I'm making positive changes in my stuttering", "I am courageous when I show bigger stutters and this courage will lead to positive changes". This is really just scratching the surface, but consciously changing your thought patterns is an important aspect of creating change. Ultimately making these changes are hard, but if you really want to do it and are willing to put in the effort, and with the right support, it's absolutely achievable.