Hi !
Depending on the photograph , your son is suffering from lip licking dermatitis.
Next Steps
Ask him to avoid lip licking with the tongue frequently.
Health Tips
Use Vaseline lip balm 4-5 times a day , use Nivea or any moisturiser 2-3 times a day . Take zincovit tablet as supplement for 1 month. If it is not subsiding , please consult with your local dermatologist or through online...