This happened to me a few years ago with old git horse, the only time he ever kicked me and he didn't mean to I just got in the way of a buck. I had a hoof shaped bruise with nail marks as he had just been shod.
Oooh, sympathies. Not nice. DD had a hoof-shaped bruise on one cheek when her naughty sheltie trod on her bum (he had got her off, she went splat onto her front and he trod on her on the way down the field - the last I saw of him were his heels kicking up in glee). Same sheltie bit me on my bum as I was leading him to his turnout a couple of weeks ago.
<now trying to think of reasons why I keep the little bugger>
Ouch, I sympathise, I really do having been bitten hard on the bum fairly recently (by a horse, nothing kinky). My sister got a kick like yours in very similar circumstances and still has a faint horseshoe-shaped dent at the top of her thigh that was thirty years ago but I'm sure you will be fine!
Perhaps you should change your name to Bishop Brennan! <waits for joke to fall flat as you've never seen Father Ted>