Hi welcome to HCMForum. it appears to be a grouth due to biting by teeth as they are irregular due to teething
of permanent teeth
it can be cured by medicines. mther possibilities are angioma
or papilloma. I advise you to consult a doctor diagnosis
Besides i advise you some diet recomendations for him as give him green leafy vegetables pulses egg milk and other protein foods
to build up immunity. and general wel being. thank you.