Hi, I read that mewing/chewing promotes chin growth, but I also read somewhere else that it causes frontal growth only, which causes the chin to look more recessed. What do you think mewing/chewing does for the chin?
It will never make your chin look recessed. It also won't grow the pogonion. What it can do is allow mandible upswing which means the mandible has the ability to protract forward, thus making more pronounced the prominence of your overall jaw.
It does not promote chin growth. If your maxilla is down and back & your teeth are messed up, your mandible is downswung and not parallel to the ground when in proper body-posture. This makes it look recessed and as if you have no chin aka a chinlet.
Mewing over time simply moves the maxilla up and forward, it corrects how the teeth meet & changes many small things in the skull which allows the mandible to swing up and forward, changing the angle, so it will look like your chin has grown, but it's the same size.
If I remember correctly there are 3 genetic defects which may cause abnormal mandible growth (looks freaky tbh). Apart from these mandible size variation is normal and with proper mewing should be proportional.