Abscess update

I kept the poultice pad on her foot, changing it every 2-3 days, from May 17-May 24. Every time I changed it there was grey matter in the pad.  The vet said in the beginning it could be just thrush but it kept producing grey matter for a week-every time I changed it. So the vet said it was the abscess opening up. I had no obvious hole in her foot. It was just coming thru a crack by the inside left heel-possibly just under the frog. Her lameness remained the same.

On the 24th I took off the poultice and continued to soak in epsom salts and water. After the first soak I noticed a red line on the inside heel. Not sure what that was. The area wasn't tender to pushing on it. Maybe the abscess was around that area and the poultice pad drained it? The vet thought so. The farrier wanted a boot put on her to help keep her hoof walls ok. I have 2 types of easy boots-one that goes up over the heel bulbs and one that someone trimmed down and is below the heel bulbs. I chose the later thinking that the other one would irritate something that was looking "angry" in the heel bulb area. The only problem with that choice was that the boot would only stay on about 1/2 a day. The lameness was improving however her hoof was chipping some-farrier wouldn't like that. I soaked once a day thru Wednesday the 28th.
On the 28th and 29th I put her in the arena to "self-exercise". She loved it, ran, bucked, kicked up her heels-you could tell she was feeling better.

On the 29th the farrier came again. We put the hoof testers on her and she wasn't as sore. She was walking better. So we decided to put a shoe on her. Only enough good hoof to have 2 nails on each side. She is still a little bit off at the trot. She will only be going in the arena until she is 100% sound, so the 2 nails should be just fine.  

So I have a vet that thinks the abscess was caused by the fourth nail on the inside of the foot.  I have a farrier that thinks it wasn't the fourth nail but was a bruise that caused an abscess. I'm caught between the vet and the farrier-both have more knowledge than me in their fields. I have to make a choice what to do in the future. The past is done and we may never know the answer as to what caused the abscess. I think I will err on the side of caution and request no fourth nails on my horses shoes. I'd rather have the horse pull a shoe than to go thru an abscess again. It took a good 3 weeks to get to the worst of this and it will probably take 3 weeks to get better. So I guess I have some more waiting to do. Another update will be coming.