Sorry you're going through LPR. You're not alone on this one, and there are some things you ca do, though they'll take time. But, to answer your questions:
1) Possibly, though it's usually a chronic condition. Now, this doesn't mean you'll be suffering all the time. Given lifestyle modifications, proper diet, exercise, posture, and medication, you'll be able to live most days without many effects.
2) No. The only short-term effect is possible "blowback" (though I don't know that to be the actual name). Basically after you stop taking your meds, your stomach will start to produce a bunch of acid for a little while. Eventually it'll calm back down again. The best thing to do is to supplement your diet with things like DGL, aloe vera, ginger root, and stomach enzymes. Of course, unless you do some lifestyle changes, all these will be bandages, at best. The point is you should help your body heal itself. Don't hinder it by eating the wrong foods, smoking, not exercising, and being overweight. (You may be doing all the right things now, so these are just some general suggestions. Don't think I'm presuming you don't exercise or are overweight.) By the way, acupuncture can help. A lot.
3) You'll have to get a barium swallow test and possibly an upper endoscopy to find out for sure whether you have a hiatal hernia.
I also had suffered from acid reflux and was prescribed Nexium. It actually worked for about a month. After that one month it did not matter if I took it at all because the acid reflux came back and worse than ever.
I realized I had to do something about it because my throat was taking to much abuse from the acid mixed with Nexium I guess. I found a book with natural remedies. I found out that acid reflux was simply an acidic imbalance and could be rebalanced by raw organic celery or an even much more powerful acidic balancer is raw organic unrefined apple cider vinegar. Remember it has to be organic or it won't work. Unless you are willing to change your eating habits your reflux will never be under control. Big Pharma would never teach a doctor this.No money in it.