I've had to deal with saddle irritations most of my cycling career - asymmetrical hips from a cx crash early on.
I have ridden when I thought it was iffy, and surprisingly, it turned out well. But I have never really had a "boil". I have ridden with slightly broken skin, but no blood or puss.
I say give it a go. May be tilt the saddle a very small bit to change pressure points.
You don't really think simply ageing may have led to this do you?
PS - the best advice I have received re: saddle problems has been from a rider-doctor, "On-the-Spot" Neutrogena zit cream, after the ride & shower. Does a nice job drying things up. Not inexpensive, but a little dab goes a long way.