I'd suggest Metamucil at this point as am almost positive it is ok to take when PG. It should help make your stools less acidic. Jeanne is probably right about the cuffitis or it could be the pregnancy is putting pressure or something that is causing the problem. Can you try to use prep H or similar suppositories? I say this as they have coco butter in them that should be soothing to the cuff if nothing else. Also check to see if this is ok with your pregnancy. The suppositories have different ingredients than the pads do, pads have more witch hazel which include alcohol. You don't want to stick witch hazel up there, ouch!
Can you tell I've read the ingredients of these things too much, lol. Remember Jeanne - we have been through and through this....together.
If you can see your GI at this late stage of your pregnancy it would be great as having a case of untreated cuffitis with a new baby is not necessary. I'm a new grandma and all those new mom memories came back watching our daughter-in-law with our grand daughter.
Best wishes!