HI! Sorry to hear that you are having such a rough time!!
Firstly, please continue to give his reflux meds. If he is "blocking" them with his tongue, you could try using a very small medicine dropper, and squirting it towards the back inside portion of his cheek. You can also blow into his face as you give him the medicine, which shoudl cause him to swallow.
The medicines generally do take some time before you have noticeable results. What med is he on? 3 weeks you should be seeing some results, but stopping it too quickly is likely to cause more problems. If this medicine isn't working, there are plenty of other meds out there that he may have more success with.
Reflux can cause aversion to feeding. If he is associating the bottle with the pain caused from reflux, he could definately refuse it. (i personally had alot of success with the Playtex nurser's as well, fwiw).
There is something else that causes aversion to feedings called Dysphagia. I don't have personal experience with this, other than knowing a woman whose son has this, but there is a link at the top of the Colic board that may be helpful - I have posted the link below.
https://babywhispererforums.com/index.php?topic=18509.0Ok, after having re-read your postings, it just hit me.....is he teethign?
?? 4 months would be the right age, not eating is common, drooling, pain....
Have you given any pain meds? Maybe you could try some tylenol or motrin half an hour or so before the next feeding, and see if that helps!!