If this has occurred, don't pick the scabs. You can apply aloe vera gel onto the scalp to help soothe the burn. The next time you go for a chemical treatment, be sure your scalp isn't irritated, and if you're carrying out the process yourself with an at-home kit, try not to go over the suggested time limits. Follow the instructions provided by the kit, use petrolatum to prevent burns and don't apply the chemicals close to your root.