The front feet are what will hurt you and if you can stay against the shoulder, there is no way the front feet, back feet, or teeth can get you. If you need to, grab a chunk of mane and pull yourself against the shoulder. You give the horse all the lead line it needs to go up. The best way to deal with rearing or pulling is not to let them get started in the first place. You do that by keeping your attention on the horse and the horse's attention on you at all times.
Nobody's perfect, however.
So if the horse does startle or pull back or rear, you just go about your business and put him right back to work. Remember, there is no such thing as a disobedience if you're not directing the horse. Pulling or rearing or jumping sideways may be a lapse of obedience but when they happen, you simply interrupt them with instructions of what to BE doing. Your primary objective in any training session whether you're working on the ground or from the saddle is rhythm and relaxation. What the horse needs is steady, physical work at a mental level that you have created which is alert enough and excited enough to pay attention to you but not frightened and not tense.