Never hit any animal! Its not a smart way to do any sort of training as it only encourages them to act out violently as well, as you are learning. Dont do it ever again. Not to your bunny, not to a dog, not to a cat, not to any animal
You need to earn her trust back. It could take a long time depending on how afraid of you she is. Lay on the floor and hold treats. Dont reach for her as she comes to grab them. Let her sniff you, and again, dont reach for her. Let her explore you. Do this as often as you can. After she gets more used to being around you, try to pet her just once every time she comes near you. If she starts to get scared, stop reaching for her and try again the next day instead. Do this back and forth until she is ok with you petting her a few times. Once she is ok with that, introduce the brush. Let her come near you, one brush stroke on her head, put the brush down. Continue like before until she is ok with it and is ok with you. Once she is, success!