Thanks for the valuable inputs..
Well you see by your own admission you have taken a spate of anti psychotic medications over a span of 20 yrs and I must tell you that these antipsychotics especially old generation antipsychotics and even newer generation anti psychotics to some extent including abilify are known to produce anti cholinergic effects which include dry mouth and this plausibly explains your chronic dry mouth.
Now it does not seem like you have Tardive Dyskinesia so better will be to bring off Cogentin because this drug is only making your symptom of dry mouth worse since it is an anti cholinergic drug itself therefore it would have made the dry mouth even worse ever since it's introduction.
So now that you are off abilify / all sort of anti psychotic medications, so once the abilify washed out of your system you will start appreciating improvement in your dry mouth , so this may take as much as 3-4 weeks at least ,. so this much patience you need to have.
Other than this you start taking vitamin b complex capsule starting with 2 capsules a day for first 15 days and next 15 days 1 capsule a day because vitamin deficiency can also lead to such dry mouth.
Along with this start eating .lots of citrus fruits like oranges , lemon juice , etc so as to get your body enough of vitamin c which could also be contributing to this condition of yours.
Also talk to your doctor to get HbA1C done so as to monitor your blood glucose pattern over last few months since diabetes can also result in a similar picture.
So you see there are many things which you got to do here, which are going to help you recover from this symptom , so kindly have patience and start following the strategy and I am hopeful you will come out of this condition soon.
You may discuss and scrutinize this suggestion with your doctor so as to reach a consensus and then follow it up with the right approach.
I hope this helps.
Wish you all the best.
Please kindly leave a Positive rating if you are satisfied with the answer.