Thanks Elcruxio for taking the time to respond in such depth

I was a little afraid to include too many details and end up with a two page post.

I wear an ASSOS T.CENTO Comfort fit designed for long distances purchased in 2015
I use copious amounts of Assos Chamois cream
I wash my riding clothes each evening with shampoo available in my hotel room
In preparation, during the year, I cycle once a week 60-80k with at least a 500m climb

I was wrong to call them blisters; they are in fact two sores, each located beneath my sit bones