The horse needs to walk.
you make it trot
See a primary health care provider; a medical doctor, osteopath, or a chiropractor.
If I read correctly you're describing a horse's chestnut. All horses have chestnuts, just like we have fingernails. It's just natural. There is no way that your horse's chestnut is what's causing him to limp. Maybe you should call in your ferrier or another horse expert to see what the real problem is.
Have the horse trot for you!
Trot. When a horse trots, its head stays level unless it has a limp in the front end. When the horse has a limp in the back end one of its hind quarters drops. If it is sound then they are level. When a horse is galloping it has a 'leading leg' - its two sides do not have the same movements so it is difficult to spot a limp.
If you think a horse is lame, you should trot it on a lead rope and jog with it to see if it is limping. If you still think the horse is lame, contact a vet.
At least walking.
Abscesses impede the horse's ability to walk normally. Abscesses are very painful, so horses will limp and will not run when they are in pain. However if the horse is given bute (a pain killer), the horse won't limp as much.
If you know the horse has a limp call the equine vet immediatly, if you dont know then i think your horse will be slower, rufuses more and you may be able too feel a slight fall as it puts its bad leg down* *please dont not take my word i am not trained or whatever im just trying to help, if your desperate too know ask your local equine vet
make it walk or trot
No; in fact, that could only worsen things exponentially. If a limp is not visible (even slightly) when the horse is walking, he's trotted in hand. It should show up then if it's there.