I have lots of experiance with stone bruises. The weirdest one I ever delt with came out thourh the coranet bad.
Either way the best thing is to soak your horses foot in epsom salt. Just once a day for a week.
The next step would be to get some hoof packing some good brands for brusing include Rabbits magic cushion or finnish line medicated poultice.
To use just get a four peices of paper cut them to you horse hoof size and put a ice cream scoop size on the papaer and put in the feet. The rabbit formula is very sticky so you will need gloves and a good spoon just apply derectly to the hoof. This will help draw out the brusing. But make sure to take it out the next day or no longer then two days. Just remeber do not do for more then a week you do not want to make the feet to soft. Just soft enough . This will help with the pain
.hope this helps I work with many thourghbreds at the track so I have to deal with this on a dalily basis.
Also as a helpful hint to all. If you do alot of riding on the road or hard surfaces. Maybe your horse did a long day of competion or your blacksmith just shod your horse. There is nothing wrong with packing your feet after. You can use just a regular hoof packing my favorite is Forshners. It will help allivate hoof pain. Just make sure to take it out in the next day or two.
Your horse will be much apperciated for it.
Hope this helps