Hi, i just hope you are not applying too much pressure while brushing your son's teeth. There may be some calculus deposit leading to the swelling of gums and since you are unable to brush the teeth properly, the condition is getting aggravated due to increase in plaque
accumulation. Please consult a dentist
, a pedodontist preferrably. Thorough scaling and use of a gum astringent
should resolve the proble. Take care!