I doubt it.
Well, it's not a good idea to reverse a bronze brush in a barrel, but if it's a nylon brush it probably won't hurt. Not sure how you would have damaged your crown with what you did, and just having done it once probably did nothing of significance. Sounds like you may have been pushing the brush down the barrel from the breach and out the muzzle and then pulling it back again. Doing a lot of this is not particularly good for the crown. It is also not necessary. Get some Wipeout Foam and Accelerator. This will get your gun clean without a lot of effort on your part, very few strokes of the rod, and NO scrubbing. Of course you always want to use a good bore guide, preferably one from Sinclair that is made to fit your rifle.
Many claim to know many things about the crown and its affect on accuracy. Precision Shooting ran an article where they intentionally messed up several crowns and the front part of the rifling and found little to no effect on accuracy. I wouldn't count on that, but I wouldn't be super-sensitive about it either. You can always examine your crown with a jeveler's loupe or magnifying glass using plenty of light. A bore scope is the gold standard for this work, however. The important things about the crown are that it be even all the way around and that it be square to the bore. Square, 11 degree or beveled all work fine.
