Since you have braids on for a very long time, you may have an itchy scalp. To treat the scalp, you can do many things. 1. Your scalp may be just dry and needs some moisture. You can apply jojoba oil, coconut oil, or olive oil on the scalp and massage gently; this way, your scalp will be moisturized and won't be itchy anymore. 2. The scalp needs to be cleaned regularly, even when wearing braids. You can shampoo your scalp without messing up your hair. Make sure to cleanse in the shower to keep the hair in a vertical position. Apply shampoo to your hands and work it onto your scalp, taking care to rub it in. The downward motion of the water will carry the shampoo onto your braids, so there's no need to work a lather into them vigorously. 3. If you're in between shampoos and your scalp still itches, try an antiseptic on the scalp only.