My 8 years old son gets cracked lips all the time and sort of pinkish rash around mouth. i suspect it is due to sodium lauryl sulfate in tooth paste. what tooth paste can he use?

I don't usually recommend baking soda (sodium bicarbonate) for children - difficult to control. Look around at the toothpastes available to you. Otherwise, keep the amount of toothpaste limited to a pea sized dab, and keep the lips and local area protected with white petroleum jelly

There are non-fluoridated t'pastes available. Tom's of Main comes to mind. If your son switches to a toothpaste without sodium laurel sulfate, there are other ways to provide therapeutic fluoride . Talk tones Dentist for recommendations.