Abscess??

Eww Tendon injuries are not fun and thanks I think he is feeling better

Just fyi - for an abscess you wont necessarily see anything until they burst...

Pressure testers can help locate them but not always... horses in NZ seem to get them alot - but it may be a climate thing...

They can start off slightly lame and end up looking like they have broken a leg....

If I suspected an abscess I would soak the foot twice a day in warm water and epsom salts.... don't put the hoof in too deep - as you don't want to go past the coronet band (or this can encourage it to burst higher)...

You can poultice the hoof to hell encourage it out... with something like iodine and sugar to help draw it out or nimal lintex (Which is like a gamgee style thing which has a built in poultice when wet... Ill often bandage when burst to keep it clean...

The relief once they have burst is huge and often they heal really fast once burst but keep the area clean...

If they don't burst in a week - you can get the vet out to help but a much cheaper option is getting your farrier out