Buck's injury -progression photos pg3

I'm seriously freaking out right now, two of our stallions broke out and I found Buck grazing happily but he has a horrible scrape on the inside of his back hock and I don't know what to do at all. No money at all for a vet, we are completely broke right now, moms at work and my dad saw it but has to bale hay today. I can try to get a picture but I don't know what to do at all,if it was something smaller I would just flush out with water or alcohol and wrap with cotton but we don't even have cotton anymore. We don't know what he did but we do know that he pulled his gate off its hinges so he could have gotten his leg somehow in that. I'm so freaked out I haven't even began to look for Leo yet.