Unless you have a special reason for keeping him in a side pull, I'd pitch it and put him in a bridle. At 4, in my experience anyway, horses enter what I call the "what-will-happen-if-I-decide" stage and this is when they start testing you. They are over the "I'm-not-sure-about-this" cautious stage, through the routine "I-get-it" stage and into the figuring out what they can and cannot do with what they know stage. And this horse has just learned that, if he chooses to, he can out-horse you - and he's likely to try it again - not because you didn't get back on, but because you couldn't control or stop him. Unless he's a psychic there is no way he could know that you couldn't get back on, only that you didn't. And let's face it, if you had of been able to get back on, would you have had any better control of him than you did before he bolted? I guess what I'm trying to say is it's not always a good thing to "get back up there" if nothing has changed. Did he take off after the fall, or did you lead him home? If you led him home, then he still didn't get home on his terms, but yours. If he took off and left you, then he made it home on his own terms, without you. Most horses don't realize how their riders got on the ground, they don't make the immediate connection between dethroning riders by bucking or bolting until it happens again. Because of this, I don't blindly subscribe to the "get back on them" mentality. I judge whether or not I can address what went wrong and work the horse through it if I remount. If I was badly shaken or hurt I usually won't remount as I don't want to risk a repeat performance which would be worse! The last thing I want to do after losing control or being thrown is remount simply to "show him whose boss" or because I "can't let him get away with that". If at any time I feel like I have to prove something to the horse, I step back and address it another day…on my terms and my time, not his. At other times I may know what went wrong, remount and work through it at that time.