Wear a helmet. You want to be able to feed yourself in the future, rather than having someone having to feed you.
I really appreciate the concern, but I don't plan on wearing one. It's not something I want to argue about though and lose a nice horsey friend-always need more of those! :D-but IMO, if I wear a helmet, might as well wear a back protector, knee pads and elbow pads, or just stay away in general, because my horse is far more likely to kick me in the back and paralyze me or me fall on my back and hurt myself seriously than that. I don't have anything against a helmet at all, I do own a little random brand one, but I've chosen not to wear one for the time being.