Acupuncture and Dry Mouth

I have had a bad case of dry mouth since March. Also had a heart attack in June. Right now I am taking acupuncture treatments for dry mouth. I have been with my doctor for about four weeks seeing him twice a week. I was getting better a few weeks ago, I went almost two weeks without a bout, then it came back and it came back hard. My two appointments are on Tuesday, and Thursday mornings. However for the last two weeks the dry mouth comes back on Saturday night, and lasts a few days until my treatment days. Is this natural, do I just need to keep the treatments going longer? The temporary relief is nice, but I would like something with a little more permanancy.