You really need to have a good frizzen to pan fit. It can be made to happen! Don't fix it with a band-aid! How it's usually done is to "smoke" either the pan or frizzen, close and open it a few times, and then file your high spots. Repeat many times. It's a chore, takes a while, but really that's what needs to be done, if indeed the prime is leaking out of the mating surfaces. You really need to have a perfect fit. A poor fit is just something that comes with the Traditions, Lymans, and other bargain flintlock locks. But it can be fixed.
3fg can help, 4fg is not necessary.
Hopefully you bumped the pan, or it didn't close all the way, and there is no problem! All that hot air for naught!