I was thinking the same thing! From what I've read (mostly from RiosDad posts) the heel should be pretty short and the frog should be touching the ground. It kind of looks like your horses is sunken in?
Well I guess its good that you're not insulted by our amateur assessments then, haha.
I would look in to getting a new farrier? Long toes/heels can cause all sorts of leg problems, in addition to killing off his frog. I don't know if it comes back once its dead....that would be something I would look in to!
I wouldn't beat yourself up for it. We all do the best we can with the knowledge we're given! Its a good thing that you sense that something was wrong and are trying to correct it, and thats all you can ever do.