Glad to hear that the pepsin tests came out negative. Even if some reflux contributed to you developing LPR, it sounds likes you don’t have any at this time. So, yeah, no need for taking a PPI.

As for other possible factors...

Dry mouth: Do you notice whether you breathe with your mouth open when sleeping? That can dry out your mouth even with normal humidity in the room, but especially so in drier climates unless you use a room humidifier. Ask Benjamin’s mom to check on that if you are not sure. But you’ll probably know yourselve b/c you would usually feel the dryness of your teeth, especially the front ones, if you sleep breathing through your mouth. In fact, doing so can contribute to tooth decay and/gum problems, as an extended lack of saliva on them can foster them. At least, that’s what a dentist told me years ago.

Excessive use of your voice, coupled with acidic beverages: The wife of a friend of mine who is a long-time opera singer and voice teacher regularly drinks herbal tea infused with honey to help soothe her throat. She swears by it, but it’s hard to say how much it actually helps versus acts like a placebo. And she also uses a humidifier in the bedroom except when it is naturally muggy.

In any event, all the best on feeling better.