When I played hockey, I had an almost permanent medial forefoot edge blister. With training and games twice per week, there was no chance they'd fully resolve until after the season ended. Here's what they looked like. This one's pretty mild, but you can tell it's rather uncomfortable with the blood in it.
My hockey medial forefoot edge blister
This morning I answered a YouTube comment about this blister location:
Thanks for sharing your knowledge of edge blisters. I’ve been getting one in exactly the same location as first one shown, the one you identify as yours. My question is what to do with the callus I get in this spot. At first I thought the callus was causing the blister and I did my best to remove the callus. But on very long runs I still get a nasty blister in this one location. Should I leave the callus or try to remove it? The blister is a blood blister and it occurs under the callus.
Here's how I answered:
OK, what you need to know is, callouses and blisters are caused by the same thing: repetitive shear deformation (stretching back and forth in the skin). Callouses are the chronic manifestation, blisters the acute manifestation. By all means reduce the thickness of the callous, but that alone won't stop the forefoot edge blister, because you haven't negated the blister-causing shear.
It doesn't sound like you've implemented an actual prevention yet. Basically, this anatomical site benefits most from two preventions. The first is Engo Blister Patches, using the two-patch technique. Here's what that looks like (below).
The two patch technique for forefoot edge blisters: Using two large oval Engo patches, apply one to the insole, and one to the side of the shoe. This creates a smooth interface for the joint. p>If that doesn't do enough to stop you forefoot edge blister, see a podiatrist. Foot function is extremely relevant and important to this blister site. A podiatrist can help minimise both pressure and bone movement at this location with things like orthoses (not just any orthotic, one with specific design features) and maybe stretches and a few other things. Hope this helps :) ~ Rebecca