Man, that's a bummer Lil`kid. I sure hope you can save the bore. You need to drop a light down there to assess the damage. Oiled steel wool and/or JB bore past may be in order.

I have no personal experience with Ballistol. A guy gave me about half of a bottle to try as a patch lube, but I never got around to trying it. It sure stinks (smells bad). He swears by it and uses it to protect his musket. It also seems to be highly thought of by many traditional rifle shooters on The Muzzleloading Forum.

Personally, I don't think I want a "water soluble" oil for protection. That just doesn't make sense to me. Just a guess, but I suspect your bore wasn't completely dry when you swabbed it with the Ballistol, and it held the moisture to the metal by preventing it from evaporating. I've gotten completely away from hot water for cleaning. I find it often causes flash rust, and cold water with soap cleans just as well.