I did a brief search before posting and found that others seem to have had some of these experiences but not focused on them topically per se.  I've noticed a series of odd symptoms(?) that may or may not be related to mewing (which I just began in earnest after 2+ years of braces and several months wearing a finisher and then a retainer), but wanted to list them for the purpose of comparing notes with others who may have noticed the same things:

- Headache: This usually results from dehydration or hunger but I had a low-grade headache for most of the day several days back, for no apparent reason.

- Facial blemishes:  I'm well past the age for acne/pimples, but I have noticed that toxins in my system, whether external (e.g., pesticides on produce) or internal (e.g., release of long-standing muscle knots/tightness) produce distinct red spots on my face or at points of muscle attachment.  Recently some small spots appeared on my left cheek - between the "apple" and lower edge of my cheekbone - again for none of the usual reasons.

- Sinus drainage:  I rarely suffer from allergies but occasionally have sinus drainage when the pollen count is extremely high.  For the past several days my throat has been "froggy" and irritated, and I've frequently felt the need to clear my throat.

- The "blahs":  This is an illness of sorts I get once or twice a year, when I don't feel sick/nauseous per se but tired and dizzy as though I should not be standing up.  A day or two of decreased activity (and extra naps) is usually all that is required.  I've also felt this way on a couple of occasions in response to a toxin release from a few days before (after which I apparently didn't drink enough water), and this morning I slept in and have been tired all morning as well as a tad achy and chilly.

So...all of these could be coincidence as they're not unusual in themselves; but all of them happening about the same time, in this sequence?  Could the shifting of my facial bones not only have produced a headache but effected a toxin release, which led to first blemishes over my cheekbone (just the left for now as the right side of my face lags behind) and now a feeling of sickness?  If so this is actually encouraging as it tells me that "something" is happening even if I can't see changes in the mirror yet.  I've just recently become able to press my tongue farther back onto my soft palate, so it could be that mewing is finally having its effect now that my teeth are allowed to shift as they need to.

It stands to reason that as adults our bodies would need to overcome more challenges to effect these facial changes than they would have as children.  So for those of you who have experienced headaches and other difficulties, don't give up!  Has anyone else noticed these symptoms?  Can anyone add to this list?