Thanks for your well wishes and perspectives, everyone. I'll never again let anyone aggressively dig away at my horses sole. It would have been better to just soak and medicate and wait...But how do you know to definitely treat for an abscess in the first place if your farrier doesn't dig at the sole? How do you know it won't burst around the coronary band?
I didn't say I wouldn't "dig" at the sole. I said I wouldn't use a powered drill bit.
I use a small loop knife designed for exploring an abscess track. If it's within reach, I'll know it usually before any significantly bleeding.
You might be surprised at just how far some of these abscess tracks can go. Once they enter the solar corium, it becomes the veterinarian's domain, not mine.
I did slather a pharmacy- worth of meds on the hoof in the past weeks; epsom salt gel, iodine (sugardine), Durasole (still using that, it can't hurt), tarry sole packing, Sore-no-more, Animalintex, icthammol, cotton, vet-wrap, duct tape and soaking boots,... obviously none of it did anything.
Horseman- I couldn't get the sole to yield to thumb pressure today. Maybe I couldn't press as hard as necessary?
Perhaps the sole is thicker than the photos suggest. That's a good thing. If the sole is excessively thin, it will yield easily to moderate thumb pressure.
I can't offer much more in the way of advise without seeing the horse in person.
Sometimes radiographs can reveal more significant issues. If you can get a set, post them here and I'll take a look.
If the horse is still lame with no signs of improvement, it may be time to get the vet and farrier together for an onsite consult and more thorough evaluation.