Perhaps give him more time off. If they are opening up easily, I would put some red scarlet oil on them.(this helped my horse when he would reopen an old wound on his leg. It helped heal it up quickly)
Other then that, I can’t tell you anything.
I have a thin skinned horse who is ALWAYS cutting himself. I put him on omega 3 horseshine and that seems to help him heal up a little faster. But not as fast as I’d like haha.
"Take the time it takes, so that it takes less time."
"Expect a lot, accept a little, reward often."