Bruises, aches and pains are a side effect of doing martial arts and weightlifting, I'm permanently covered in them. Rolling should be taught to you in class, and if it isn't being done well, I'd think about changing class. A good Judo class will teach you to roll and breakfall. That being said, I always ache the day after Judo, it's natural when you are throwing your body around like that. I recommend investing in an ice pack, a heat pad, some Radox Muscle Soak bath foam, a foam roller and occasional sessions of deep tissue massage with a qualified practitioner. Stretching and strength training will help with you rolling, as you will gain better control of your body.
Don't try to remember every technique you learn in class. Pick one or 2, write them down in a journal and mentally run through them when you having nothing better to do.